Income adjustments add money to the portfolio in years they apply. Each type has slightly different defaults. Taxability, freeze-until-retirement availability, and which life events can anchor its timing.

Take-Home Salary (deprecated)

Job

Wage or salary income that is fully taxable in the year earned. Use this for primary jobs, side income, contract work, or any W-2 / 1099 inflow during working years.

A Job's pay fields are in three sections. Salary and Take-Home Pay holds your gross salary and shows the estimated take-home pay it produces. Paycheck Deductions holds benefit deductions and any other amounts taken from the paycheck. Retirement Contributions lists the Cash Flow Priorities funded from this paycheck and what your employer adds. A closed section shows a one-line summary of what it holds.

Other Payroll Deductions is for paycheck deductions nothing else models: state disability or paid-leave premiums, local income tax, union dues, supplemental life insurance. It starts at 0%, and 0 to 2% is typical. Leave income tax out of it: FIREproof calculates federal tax, and state tax too once you choose your state on the Parameters tab (New York City includes city tax), and the Estimated Net Pay card shows both. The card uses your plan's filing status (set on the Parameters tab; with none set, Single for one person and Married Filing Jointly for two) and applies no tax credits. Health premiums, FSAs and pension contributions go under Benefit and payroll deductions, which also applies their pre-tax treatment. This amount comes out after tax and does not lower your taxes.

Employment Income typically ends at the retirement year, but you can extend it (semi-retirement) or end it earlier (sabbatical, planned exit). When paired with retirement-account contributions in Cash Flow Priorities, this is the source the engine uses to fund 401(k), IRA, and HSA caps.

Self-employed income

Check Self-employed on a Job when you pay your own Social Security and Medicare tax, as a 1099 contractor or sole proprietor does. Instead of an employee's 7.65% FICA, the Job pays self-employment tax: 15.3% on 92.35% of your profit (the Social Security part stops at the yearly wage base). Half of it is deducted from your income before income tax, so your income tax is a little lower than an employee's on the same pay. The Estimated Net Pay card shows it as Self-employment tax. A Side Hustle always pays it. One exception: an S-corp owner whose Solo 401(k) uses S-Corp W-2 wages keeps ordinary payroll FICA, because that salary is W-2 pay. FIREproof does not reduce the self-employment wage base for W-2 wages from another job.

Benefit and payroll deductions

A Job can carry the deductions taken from its paycheck: an employee pension contribution, a health FSA, a dependent-care FSA, insurance premiums, or anything else. Click Add a deduction in the Job's Paycheck Deductions section and pick one; each deduction is then a row showing its tax treatment and yearly amount, which you click to edit. Each one has a tax treatment, copied from your pay stub:

• After-tax lowers take-home pay only.
• Pre-tax for income tax also lowers the wages you pay income tax on. Most public-employee pension contributions work this way and still pay Social Security and Medicare tax.
• Pre-tax for income tax and FICA also lowers the wages you pay Social Security and Medicare tax on. FSAs and cafeteria-plan premiums work this way.

Enter your own election; FIREproof does not check benefit limits across jobs or spouses. With an FSA, budget only the costs it does not reimburse, because the paycheck deduction already paid for the rest. Your 401(k) contributions and employer match stay on Cash Flow Priorities and are still figured on your full salary. If you move an amount here from Other Payroll Deductions, lower that field by the same amount. Your state income tax follows the same wage exclusions (a few states tax some of these; that is not modeled). These treatments are US rules, and they are not available on self-employed income. To see what they did in a given year, open the Proof page's Taxes tab, click the year, and expand Wages, payroll tax.

HSA contributions through payroll

A Cash Flow Priority that targets a Health Savings Account and names this Job as its paycheck is treated as a payroll HSA election. It comes out before income tax and before Social Security and Medicare tax, the way a cafeteria-plan election does, and the Job's Retirement Contributions section lists it under your pre-tax contributions. Maximize fills the yearly HSA limit for the account's coverage type (plus the catch-up from age 55) less whatever the Job's employer HSA contribution adds, because the limit is one combined cap. In the results, the Job's payroll row shows it as HSA (pre-tax). Two limits: on a self-employed Job the contribution still lowers income tax but not self-employment tax, since there is no cafeteria plan; and an HSA priority with no paycheck linked is funded from leftover cash after tax, with no deduction modeled.

Pension

A recurring inflow that typically starts at or after a person's retirement year. Pensions are usually fully taxable as ordinary income at withdrawal. Many pensions are not inflation adjusted, so use the Not Inflation-Adjusted setting if your plan is fixed.

The Freeze Value Until Retirement option keeps the entered amount flat until its start year, so the year-1 payout matches what you typed instead of being scaled up by pre-start inflation.

Social Security

A recurring inflow tied to a claim age. Social Security is partially taxable based on combined income; the engine applies the standard provisional-income calculation each year. You can model spousal claims independently when there are two people.

Use the start-age control to model claiming early (62), at full retirement age, or delayed (up to 70). The engine does not auto-optimize claim age. It models exactly what you enter.

Custom Income — periodic windfalls

Use a Custom Income with the "Occurs at regular intervals" toggle to model lumpy inflows that repeat on a fixed cadence — royalty distributions every 3 years, a milestone bonus every 5 years. Set Repeat every (years) to the cadence; the income fires in the Start Year and again every N years through the End Year, inheriting the same inflation rule (CPI, Flat Rate, or none). The toggle isn't offered for Job, Side Hustle, Pension, or Social Security — those types are inherently continuous.

Other Income

A flexible inflow for anything that does not fit the categories above: rental income, royalties, annuity payments, or a planned windfall. Choose the inflation rule and tax treatment per the income's real-world behavior. For example, an inherited Roth distribution might be flagged Treat as post-tax.

Side Hustle

A recurring secondary income stream. Consulting on the side, freelance work, a small online business. Defaults to flat-rate growth (2% / yr) and is taxed as ordinary income in the year earned, plus self-employment tax. Use it when you have income that runs alongside a primary salary or that continues into semi-retirement on a different timeline than your main job.

If a side hustle is significant enough to drive retirement-account contributions through the paycheck, treat it like a self-employed Job instead so the contribution-cap logic kicks in. Side Hustle is best for smaller cash inflows that don't need that machinery.

Inheritance

A one-time influx of cash arriving in a single future year. Inherited cash and property are not income to the heir under US tax law, so Inheritance is not taxed by default: Treat as post-tax starts on. Turn it off only for money that is taxable when you receive it, such as a lump-sum cash-out of an inherited Traditional IRA or 401(k), which is ordinary income in the year received.

Inheritance is one-time, not recurring, so the start year and end year are the same. It is deposited into the simulation's cash flow that year and then routed by the Cash Flow Priorities rules. Any leftover surplus is handled by the Save-vs-Spend selector on the Cash Flow tab - in Save mode (the default) it lands in your brokerage account; in Spend mode it counts as discretionary spending.

Inheriting a retirement account is different. A Traditional IRA gets no step-up in basis, so it does not arrive as spendable cash - it arrives still inside the tax-deferred wrapper, with the SECURE-Act 10-year clock starting at the date of death. To model that, add an Inherited Traditional IRA or Inherited Roth IRA account on the future-inheritance path and pick it from this event's Deposits into inherited IRA selector. The proceeds are deposited into that account, are not taxed on arrival, and the forced distributions begin the year after. Leave the selector on Cash inheritance for everything else - taxable assets do get a step-up, so they are correctly modeled as a plain cash inflow.

A linked Inheritance event must be one-time, and each inherited account can be funded by at most one event. See the Accounts help page for the account side of the setup.

Spending Reduction

Not technically income. Spending Reduction represents money you choose not to spend. The simulation models it as a recurring offset against base living expenses, so the practical effect on the portfolio is the same as a recurring inflow of equal size: less needs to be withdrawn each year.

Use it for plan changes that shrink your retirement spending without changing your Base Living Expenses figure: downsizing to a cheaper house, dropping a country-club membership, or moving to a lower-cost-of-living area in year five. The recurrence and start / end years let you scope exactly when the reduction applies.

Treat as post-tax

Every income type carries a Treat as post-tax toggle. Turning it on tells the simulation the money is already taxed before it reaches you, so it behaves like take-home pay: it covers that year's expenses first, and only what is left over is invested according to your Cash Flow Priorities. Nothing is sold from the portfolio to fund spending the income already covered, and no capital gains are realized in the process.

Good uses: an inherited Roth distribution, cash from an estate that is not taxable to you, or any net figure you have already worked out by hand.

Two exceptions keep their older behavior. An Investment Contributions row is a savings-rate entry, so the full amount is deposited rather than spent. Any income row pointed at a Specific Account is directed money (a 529 gift, an HSA contribution), so it lands in that account instead of offsetting household spending.