Set Tax Country to Netherlands on the Parameters tab and FIREproof switches the whole plan onto the Dutch system. The account-type picker narrows to the accounts that exist there, and the year-by-year tax detail starts using Dutch names instead of American ones.

The three boxes

Dutch income tax is split into three boxes that are never netted against each other. Income in one box cannot offset a loss in another, which is why a Dutch plan can look unfamiliar beside a US one.

• Box 1 - work and home. Salary, self-employment income, pensions, AOW state pension. Modeled. The national-insurance premiums are part of the Box 1 rate, so a Job in a Dutch plan has no separate payroll-tax line the way a US Job has FICA.
• Box 2 - substantial interest. Distributions from a company you own at least 5% of, i.e. your BV. Modeled.
• Box 3 - savings and investments. Today, a tax on wealth rather than on income. Modeled, under either the current rules or the 2028 reform - your choice.

Box 1: income from work and home

2026 rates, below AOW age:

• Up to EUR 38,883 - 35.75%
• EUR 38,883 to EUR 78,426 - 37.56%
• Above EUR 78,426 - 49.50%

That first-bracket rate bundles income tax with national insurance contributions. Once you reach the AOW state-pension age the AOW contribution stops, and the first bracket drops from 35.75% to 17.85%. FIREproof resolves your AOW age from your birth year and month and uses the official weighted rate in the year you cross it. The full-year rate change is worth roughly EUR 6,960 before credits.

FIREproof assesses Box 1 and the tax credits separately for each person. Fiscal partners still pool Box 2 and Box 3, and an equal share of those pooled amounts enters each partner's own verzamelinkomen for credit phase-out. A mixed-age couple therefore uses two different Box 1 rates in the same year when only one partner has reached AOW age.

Your own home (eigen woning)

A property marked as your primary residence is an eigen woning, and FIREproof taxes it in Box 1 rather than Box 3. Each year the eigenwoningforfait, a notional income on the home, is added to Box 1: 0% of the WOZ value up to EUR 12,500, 0.10% to EUR 25,000, 0.20% to EUR 50,000, 0.25% to EUR 75,000, 0.35% from EUR 75,000 to EUR 1,350,000, and above that EUR 4,725 plus 2.35% of the excess. The property's WOZ value field in the Dutch home card of the editor drives it; leave the field blank and the modeled property value stands in, which runs a little high because the WOZ lags the market.

Mortgage interest on the home is deducted from that forfait (hypotheekrenteaftrek), but at no more than 37.56%: the tariefsaanpassing adds back 11.94 points of tax for interest that would otherwise have saved tax at the 49.50% rate. The correction runs over the interest and costs you deducted, not over the net of the forfait, so it still applies in a year the forfait exceeds them (the Belastingdienst's own Hillen example). It limits the tax benefit of the deduction, never the interest you pay. When the forfait exceeds the deductible costs, the Hillen relief (Wet Hillen, the "no or small mortgage" rule) removes 71.867% of the excess in 2026. That percentage falls about 4.8 points a year and is gone from 1 January 2041, so a mortgage-free home pays a little more Box 1 tax each year the plan runs.

A boeterente is the one-time charge a lender levies when you prepay or refinance a fixed-rate mortgage early. Under the Netherlands, the property's Mortgage section offers an early repayment charge: pick the year, enter the amount prepaid or refinanced and the charge as a percentage of it, or enter a fixed charge instead. The charge leaves the plan's cash flow in that year like any other property cost and is deducted from Box 1 alongside the interest. Only the charge is modeled here; the prepayment or refinance itself is entered through the mortgage fields (remaining balance, custom payment).

An interest-only loan is a Box 3 debt

Only a loan you repay at least annuity-style within 30 years counts as eigenwoningschuld. An interest-only (aflossingsvrij) loan taken out after 2013, or the interest-only half of a split mortgage, does not: its interest is not deductible in Box 1, and instead the outstanding balance is a Box 3 debt that reduces your Box 3 base above the EUR 3,800 per-person threshold. Under the 2028 reform and the tegenbewijsregeling the interest on that part also counts as a negative Box 3 return. Enter it as the Box 3 share of the mortgage (a percent) in the property's Dutch home card. Leave it at 0 for an annuity or linear mortgage and for an interest-only loan from before 2013, which is grandfathered into Box 1. To hold the balance flat, set the annual payment override to the interest alone. The home itself stays an eigen woning with its full forfait; only the loan is split.

Box 2: money out of your BV

A distribution from a company you hold a substantial interest in is taxed at 24.5% on the first EUR 68,843 and 31% above that. Two things about this catch people out:

• Box 2 taxes the distribution, not the gain inside it. Take EUR 100,000 out and the whole EUR 100,000 is the tax base, regardless of what you originally paid for the investments. The company's own gains were already taxed at the corporate layer.
• Fiscal partners each get their own first bracket. Selecting Fiscal partners gives the plan a doubled EUR 137,686 band at 24.5%, because Box 2 income can be allocated freely between partners. On a EUR 165,000 distribution that is worth about EUR 4,475 a year.

The BV holding company

Add a BV (Personal Holding Company) account and FIREproof models it as a separate taxpayer rather than as a tax wrapper. Two layers apply, in order:

1. Corporate income tax (vennootschapsbelasting) on the BV's own profit each year: 19% on the first EUR 200,000 and 25.8% above. Profit means the dividends it receives plus gains it realizes on sales inside the company.
2. Box 2 on whatever it then distributes to you.

Combined, that is about 38.8% at the low rates and 48.8% at the top. The reason the structure exists is that profit you leave inside the BV pays only the first layer - the second is deferred until you take the money out, and unrealized growth is not taxed at all.

A loss year is worth money twice over. It carries back one year, reclaiming the corporate tax the BV paid on the previous year's profit as a refund into the same company; whatever the previous year cannot absorb carries forward with no time limit against later years, subject to the statutory cap of EUR 1,000,000 plus 50% of profit above that. Each BV fills its own EUR 200,000 first bracket; two BVs do not share one. Expand the Corporate tax row in any year to see the profit, the carryback, the refund and what is left in the loss pool.

BV dividends remain inside the company and reinvest; they are not household spending cash. Every sale records the BV's signed gain or loss for corporate tax as well as any gross Box 2 distribution to you. The BV also pays its own corporate-tax bill before FIREproof funds your personal spending. If that BV cannot cover the bill, the year fails rather than taking the money from a personal account or another BV.

Box 3: a tax on what you hold

Box 3 is the part of the Dutch system that surprises people most: it does not tax what your investments earned, it taxes what they are worth. Each January 1 your savings and investments are assigned a deemed return, and 36% of that is the tax - whether you actually made money or lost it.

One consequence worth stating plainly: what you paid for an investment never enters the calculation. That holds under all three systems - the deemed return applies a percentage to the January 1 value, and both the counter-evidence rule and the 2028 reform measure the change from one January 1 to the next. So FIREproof does not ask a Dutch plan for a cost basis on a brokerage account. It still asks a BV for its book value, because that is a company figure and drives corporate tax, not your personal tax.

2026 figures:

• Bank deposits (checking, savings) - deemed return 1.28%, so roughly 0.46% of value in tax each year.
• Everything else (brokerage, investment property) - deemed return 6.00%, so roughly 2.16% of value.
• Debts reduce the base at a deemed 2.70%, but only the part above EUR 3,800 per person.
• Exemption: EUR 59,357 per person, EUR 118,714 for fiscal partners.

The order matters and is not the obvious one. The deemed return is worked out on your gross assets first, and only then scaled by the share of your wealth that sits above the exemption. Subtracting the exemption and then applying the deemed return gives a different answer as soon as you hold both savings and investments, which is why FIREproof follows the statutory order.

Money inside a BV is not in Box 3. Those assets belong to Box 2 and the corporate layer, so they are not taxed twice. Your own home is not in Box 3 either - it belongs to Box 1.

Choosing a Box 3 system

The Netherlands intends to replace the deemed-return system with a tax on the return you actually earn, from 1 January 2028. The bill is not law yet, so the Tax Country card offers three settings and defaults to today's rules:

• Current law (deemed return). The system described above, for the whole plan. This is the default, so nothing you saved before this option existed has changed.
• Switches to actual return in 2028. Today's rules through 2027; no Box 3 charge is settled in 2028 while the reform's first return awaits its 2029 assessment; then actual-return charges begin. The most realistic setting if the bill passes as drafted.
• Actual return from the start. The reform for the whole plan, so you can see its full effect rather than waiting a couple of years for it.

The tegenbewijsregeling is a separate checkbox, not a fourth setting. Two different things are called "actual return" in Dutch coverage. The three settings above are about the 2028 reform. The tegenbewijsregeling is today's counter-evidence rule: under current law you pay the lower of the deemed result and your actual return. Tick Apply the tegenbewijsregeling on the Tax Country card and every year charged under today's rules pays that lower figure. Its "actual return" is not the reform's: it has no allowance, deducts no costs (only the interest on a Box 3 debt), counts unrealized gains including a second home's year-on-year value change, adds an own-use amount for a second home you do not let, and a losing year simply floors at zero with nothing carried forward. With the checkbox on, each tax year is settled a year in arrears, like the reform path: the deemed result and the actual return are both measured for the same tax year, and the lower one is charged the following year. So the first year of a plan charges nothing (its deemed result is provisional and settles in year two), and the final year's Box 3 falls outside the horizon. The Box 3 drill-down names the tax year each row settles, shows both candidates and names the one that was charged. Recommended on.

Under the reform, the base is the return you actually earned, including gains you have not sold. The rate stays 36%, but almost everything else changes:

• The EUR 59,357 wealth exemption becomes an EUR 1,800 income allowance. That is the single biggest difference, and it is why small portfolios are hit hardest by the switch.
• A losing year costs nothing, and the loss carries forward against later years (the first EUR 500 of a loss is not carried forward).
• Property is taxed when you sell it, not annually, so its gain lands in one year rather than accruing.

How much difference does it make?

The deemed system charges 6.00% x 36% = 2.16% of your investments whatever happens, so the two systems cost about the same when your real return is near 6%. Below that the reform is cheaper, above it the deemed system is. The exact break-even depends on your portfolio size, because the wealth exemption is worth far more to a small portfolio than an income allowance is:

• EUR 100,000 - deemed tax EUR 878 a year (0.88% of value), break-even at a 4.24% return.
• EUR 500,000 - deemed tax EUR 9,518 (1.90%), break-even at 5.65%.
• EUR 2,000,000 - deemed tax EUR 41,918 (2.10%), break-even at 5.91%.

Investment property

A property you rent out is a Box 3 asset in the Netherlands, not a Box 1 income source. FIREproof does not charge Dutch rent as income tax; it reaches your tax bill through Box 3 instead, and how it does so depends on the regime.

• Under current law (deemed return), the rent is not taxed separately at all. The deemed return already stands in for whatever the property earns. The property's value is charged at the 6.00% deemed rate, and the mortgage on it reduces the base at 2.70%.
• Under the 2028 reform (actual return), the property's direct return is the greater of its actual gross rent and the vastgoedbijtelling (3.35% of the WOZ value), less maintenance and mortgage interest. So a property rented at a market rate is taxed on the rent, while an under-rented or self-used second home is taxed on the 3.35% floor instead of on its near-zero cash rent. The property's own rise in value does not count each year: that waits until you sell, which is the one place the reform keeps the old realization-based treatment.

Only maintenance deducts each year under the reform - property tax, insurance and management are not on the factsheet's list. A property's WOZ value and (for a mixed-use second home) its personal-use share and any capital improvement are fields on the Real Estate editor under the Netherlands. The personal-use share is the part of the year the home is available to you; the rent you collect is entered separately and is never inferred from it. Under today's counterproof a half-rented home carries both the rent for the let half and the own-use addition for the other half. A capital improvement with a year is paid from your plan in that year, like any other one-time cost, and from then on raises the property's basis, so it shrinks the gain taxed when you sell. Improvement costs are never deducted annually. Leave the year blank for work completed before this plan: it counts toward the basis only and moves no cash.

Worked example: a EUR 400,000 rental with a EUR 250,000 mortgage at 4% (so EUR 10,000 of interest), EUR 18,000 of gross rent and EUR 800 of maintenance.

• Current law: roughly EUR 5,300 a year, charged on the property's value less the mortgage, whether or not it made money.
• The 2028 reform, rented at market: the rent (18,000) beats the bijtelling (3.35% x 400,000 = 13,400), so (18,000 - 800 maintenance - 10,000 interest - 1,800 allowance) x 36% = EUR 1,944, with the year's appreciation deferred to the sale.
• The 2028 reform, under-rented (say EUR 9,600 of rent): now the bijtelling wins, so the base is 13,400 - 800 - 10,000 = 2,600 rather than the cash rent - the floor is what stops a barely-rented home from being taxed on almost nothing.

Selling a property

• Under current law, the gain is not taxed at all. You have already paid the deemed return on the property's value every year you held it, which is what that charge is for.
• Under the 2028 reform, the whole gain counts as that year's Box 3 return. This is the one asset the reform still taxes on realization rather than as it accrues.
• Your own home is taxed in neither, because it was never in Box 3.

Sizing your Box 2 distribution

Box 2 taxes distributions from a company you own at 24.5% on the first EUR 68,843 per person (EUR 137,686 for fiscal partners, who allocate Box 2 income freely between them) and 31% above that. Because you choose how much your BV distributes each year, that step is the largest single lever in a Dutch BV plan.

Turn on "Hold BV distributions at the 24.5% Box 2 band" in the Tax-Efficient Withdrawals panel and the plan distributes only up to the ceiling, funding the rest of the year from your personal accounts. It does not change how much you spend, only where the money comes from.

In a year your personal accounts cannot cover the rest, the plan distributes past the ceiling rather than failing, and the year-by-year records that it did. The setting is a preference, not a spending cut.

Note that the ordinary bracket-filling controls disappear when your Tax Country is the Netherlands. Those size a withdrawal from a pre-tax retirement account against an income tax bracket, and a Dutch plan has no such pool to draw on: pensions pay out on their own schedule and personal investments are taxed on wealth rather than on gains.

State pension (AOW) and private pensions

The AOW is the Dutch state pension. Add it on the Inflows & Outflows tab as a Social Security event, which FIREproof labels "AOW (state pension)" when your Tax Country is the Netherlands. Two things differ from the American program the field was originally built for, and the form reflects both: AOW starts at the statutory age for your birth month (there is no early or delayed claiming, so those controls are hidden), and it is fully taxable Box 1 income rather than partly sheltered.

When you do hold a pot, two account types are available under the Netherlands:

• Pensioen (Employer Pension). Pillar 2, the occupational scheme your employer runs. Fund it from a Job the same way an American would fund a 401(k), with an employer contribution alongside your own. Contributions come out of your Box 1 income before tax.
• Lijfrente (Personal Annuity). Pillar 3, the self-directed annuity, used by the self-employed and by anyone with a pension gap. Contributions are deductible up to your jaarruimte.

Lijfrente contribution room

Jaarruimte is 30% of your premiegrondslag - the previous year's Box 1 income, capped at EUR 137,800, minus the AOW franchise of EUR 19,172 - up to a maximum of EUR 35,589, less what your employer scheme accrued for you. FIREproof computes it from the income the plan recorded last year, so a lijfrente premium reduces the Box 1 income you are taxed on, exactly as it does on a real aangifte.

The room is one pool per person, not per account. Belastingdienst applies the maximum across all of your lijfrente products combined, so two lijfrente accounts share one deduction rather than each granting you a fresh one.

The contribution-limit override is your total deductible room. Set it when you know something the app cannot see - carried-forward reserveringsruimte, a prior-year shortfall, or your real factor A. Money paid in within it is deducted; it raises the deduction, not just the ceiling. Because the room belongs to the person, every lijfrente account for one person must state the same figure, and FIREproof refuses a save that sets two different ones.

Anything paid in above the room is a non-deducted premium, and Dutch law lets only part of it come back untaxed. Under the saldomethode, eligible non-deducted premiums are recovered first: payouts are untaxed until that pool is empty and fully taxed after - it is not spread pro rata across the pot. For premiums paid from 2010 onward the amount that becomes eligible is capped at EUR 2,269 per person per year across all your lijfrente products; anything above that cap is taxed on the way in and again on the way out. The Box 1 row's decision panel shows what was deducted, what was banked, and what is left to recover.

If your pension is an older defined-benefit promise with no balance you own, do not create an account for it. Add it as a Pension event on the Inflows & Outflows tab instead, which is what a fixed yearly payment from a scheme is.

Tax credits

Dutch heffingskortingen reduce your tax rather than your income, and FIREproof applies them across all boxes - against a Box 2 bill (which is why a modest distribution can come out taxed at less than 24.5%), and whatever Box 1 and Box 2 cannot use offsets your Box 3 wealth tax, so an early retiree with no income still gets their credit.

• Algemene heffingskorting: up to EUR 3,115 before AOW age and EUR 1,556 for a full AOW year, phasing out above EUR 29,736.
• Ouderenkorting: up to EUR 2,067 once you reach AOW age, phasing out above EUR 46,002.
• Alleenstaandeouderenkorting: EUR 540 for a single AOW recipient.

Both phase out on your verzamelinkomen - your combined income across all three boxes, not just Box 1. A large Box 2 distribution can therefore wipe out a credit you would otherwise have received.

Reading your Dutch tax rows

In the Year-by-year view, open Taxes and click any Dutch row to see why the number is the size it is. Four rows explain themselves:

• Box 3 shows the whole calculation. Under the current rules that is the deemed return on your savings and your investments, the debt offset, the share of the base that sits above the allowance, and the 36% rate. Under the 2028 reform it is the year's return, the carried loss it consumed, the allowance, and - the number you cannot work out from anything else on the page - how much loss is left for future years. The row expands a second time to show which account or property produced each part of the charge.
• Box 2 shows the 24.5% band, how much of it you had already used, and what was distributed. If the cap gave way because your personal accounts could not cover the rest of the year, it says so and tells you the excess paid 31%.
• Your heffingskortingen show as a before/after stack under the row they reduced - Box 1 normally, Box 2 if you have no Box 1 income (the usual case for a BV owner living on distributions), and Box 3 if you have no income at all - the usual case for an early retiree living on savings, whose credit mostly cancels the wealth tax. The stack also shows your verzamelinkomen against the phase-out band, which is what explains a credit smaller than the maximum, or gone entirely.
• Corporate tax (BV) shows the year's profit, the carried loss it used, the split across the 19% and 25.8% bands, and the loss pool remaining.

What is approximated

• Lifetime pension payouts. A real annuity pools longevity risk and pays more each year than the balance divided by your remaining life expectancy, in exchange for the balance disappearing when you die. FIREproof uses the simple division, so it understates the income slightly and overstates what is left behind.
• The pot stays invested during payout, which models a variable annuity. A fixed annuity would lock in a rate at conversion.
• Contribution room. A pillar 2 scheme sets its own ceiling, which FIREproof cannot know, so no limit is enforced on a Pensioen. Jaarruimte on a lijfrente is computed from your previous year's Box 1 income - see "Lijfrente contribution room" above for what the override means and why the first simulated year has no room.
• Factor A is approximated. The statutory formula subtracts 6.27 x factor A, the value your pillar 2 scheme accrued for you that year. FIREproof has no scheme data to derive that from, so it substitutes your actual Pensioen contributions for the same year. That is right in shape - pillar 2 accrual consumes pillar 3 room - and only roughly right in size. If you know your real factor A, fold it into the contribution-limit override instead.
• Contributions are a percentage of gross pay, where Dutch schemes use the pensioengrondslag (pay minus the AOW franchise). Enter an effective percentage of gross.

• Birth dates beyond the published AOW table. The SVB table currently ends with December 2000. FIREproof falls back to age 67 outside the published range, so revisit a very young person's plan when the official table is extended.
• Arbeidskorting (the employment credit) IS modeled, on your wage income (a job or self-employment), including the reduced AOW-age variant. It does not apply to Box 2 or corporate income.
• Box 3 covers your cash, brokerage and investment property. A rental property counts at its value with its mortgage as a Box 3 debt. Your own home and its mortgage are excluded - they belong in Box 1, where they are modeled (see "Your own home (eigen woning)" above).
• Your BV's investments are valued at cost or lower market value, the standard treatment: unrealized gains are deferred, and a fall below cost is recognized as a loss. If your accountant instead values at market - or the fund has VBI status, where it is mandatory - your real corporate tax will be higher than the model shows, because unrealized gains would be taxed annually.

Healthcare contributions

The income-dependent Zvw contribution is a separate levy from the national insurance bundled into the Box 1 rates, and it is a real yearly cost in retirement. For 2026 it is 4.85% of your contribution income up to EUR 79,409, per person - so at most about EUR 3,851 each.

• Your AOW, pension and lijfrente are assessed on you. The provider or the SVB withholds the 4.85% from the payment.
• Self-employment profit is assessed on you too, on an aanslag.
• A salary is not. Your employer pays a separate 6.10% werkgeversheffing on top of your gross pay; it never comes out of your wages, so FIREproof charges nothing on employment income.

Two related costs are not modeled. The flat nominale premie you pay your insurer is an ordinary expense - add it as a spending event if your base spending does not already cover it. The zorgtoeslag (healthcare allowance) that offsets it for lower incomes is means-tested on a household income test FIREproof does not run, so a plan entitled to it will look slightly more expensive than reality.

The Zvw contribution is the only healthcare levy a Dutch plan carries. The US Medicare surcharge (IRMAA) that FIREproof charges American plans from age 65 has no Dutch equivalent and is never charged here, so it does not appear as a column in your Statistics Summary.

What is not modeled

This is the canonical list. The engine's country file and the tax-country notes point here rather than repeating it, so there is one place to check what a Dutch plan is and is not telling you.

• The nominal healthcare premium and the zorgtoeslag - see the healthcare section above. The income-dependent contribution IS modeled, as an opt-in spending line.
• The personal credits. The algemene heffingskorting, the ouderenkorting, the single-senior credit AND the arbeidskorting (the employment credit, worth up to several thousand euros a year to a working person) are all modeled - the arbeidskorting on your wage income, with its reduced AOW-age variant. Family and green-investment credits are not.
• WOZ valuation. Both your own home and a Box 3 investment property now have a WOZ field (see "Your own home (eigen woning)" and "Investment property" above); the 2028 reform's 3.35% vastgoedbijtelling is charged on it. Leave the field blank and the property value you entered stands in. WOZ tracks market value with a lag, so the difference is roughly a year or two of appreciation.
• Domestic dividend withholding on a BV distribution. A BV withholds 15% and you credit the same amount in your return, so it changes when the money moves rather than how much tax you pay. FIREproof already settles tax a year late, which is a larger timing difference than this one.
• Reserveringsruimte, the unused lijfrente room you may carry forward from the last ten years. Jaarruimte itself is computed from your income. Enter your total deductible room on the account to model carried-forward room - see "Lijfrente contribution room" above.
• Fiscal partners split Box 2 and Box 3 evenly, 50/50. Dutch partners may allocate those pooled components between them however they like, and a different split can preserve more of the lower earner's credits. The equal split is a valid election and it is what FIREproof assumes; there is no allocation field and no optimizer, so a couple whose real return allocates unevenly will see a different total.
• Interest inside a total-return series. A BV's bond-ladder coupons and inflation accretion ARE recorded as corporate income. But when a market series bundles interest into a single total return, FIREproof cannot separate the income component, so it appears as unrealized appreciation and is deferred until the position is sold rather than taxed each year. That understates a BV's annual corporate tax and overstates its deferral the more of its return comes from interest.
• The Zvw contribution is settled a year late, like every other tax in FIREproof, so the final simulated year's liability falls outside the horizon and is never paid. On a long plan that is one year of a levy capped at about EUR 3,851 per person.
• The tegenbewijsregeling is modeled only when its checkbox is on, and it settles each tax year a year in arrears (both candidates measured for the same tax year), so a plan's first year charges no Box 3 and its final year's Box 3 is never settled, exactly as under the reform path. With the checkbox off, the current law setting always charges the deemed return, so your Box 3 tax is overstated in flat and falling years. A second home's own-use addition uses its WOZ field (or the modeled value when the field is blank), prorated by the personal-use share; its year-on-year value change still uses the modeled value. The rule ends when the 2028 reform lands, so the actual-return settings do not need it.
• The 2028 reform's finer points. The reform itself is modeled (see above), but it is still going through the legislative process and the bill's details may move. FIREproof models the headline design: 36% of the actual return including unrealized gains, an EUR 1,800 per-person allowance, losses carried forward above EUR 500, and property taxed on sale.
• Transaction and advice costs. Account costs are deductible under the 2028 reform and FIREproof takes both kinds an account editor can hold: a percentage of the balance and a fixed annual amount (open it with "Add a fixed annual fee" under the Fees field). Per-trade transaction costs and advisory fees billed outside the account are not modeled; add them to the fixed annual fee if they matter to you.
• Box 3 timing. The tax is charged against the same year's opening balances rather than being settled a year later as the real system does. That shifts when the money leaves, not how much.
• The scheduled 2028 seam and final actual-return year. The scheduled setting charges 2026-27 under the deemed system, charges neither system in 2028, and first settles 2028's actual return in 2029. Likewise, the last simulated year's actual return has no following year in which to settle, so it is not charged inside the plan horizon.
• Eigen woning fine print. The home itself is modeled in Box 1 (see "Your own home (eigen woning)" above), but not: the 30-year limit on the interest deduction; the grandfathering of pre-2013 interest-only loans; the bijleenregeling, which trims the deductible debt on a next home by the gain on the last one; rentemiddeling, where a penalty is folded into a higher go-forward rate instead of paid at once; and the rule that interest on money borrowed to pay a boeterente is not deductible. The repayment requirement itself is not checked: the mortgage is qualifying eigenwoningschuld except for the Box 3 share you enter.
• The 30% ruling for incoming expatriates.
• Gebruikelijk loon, the customary salary a working director-shareholder must take from their BV. If it applies to you, model it yourself by adding a Job under Inflows and Outflows - it is Box 1 income like any other salary.
• Other ways money can cross the company boundary. FIREproof treats an owner withdrawal as a dividend distribution. It does not model shareholder loans or a tax-free repayment of recognized paid-in capital. The 15% domestic dividendbelasting withholding is also omitted because the shareholder normally credits it in the same return; that changes timing, not the total annual Box 2 tax modeled here.
• The participation exemption (deelnemingsvrijstelling), which needs a 5% holding and so does not reach a diversified ETF portfolio.
• Foreign dividend withholding tax on a BV's international ETFs, which is often not fully creditable against Dutch corporate tax. This is a real cost the model omits.