An estimated income amount is a forward-looking projection of what you expect to earn during a calendar year, used by the IRS, the Health Insurance Marketplace, lenders, and other agencies to make decisions before your actual earnings are known. It is not what you already reported on last year’s tax return. It is your best prediction of this year’s total, built from what you have earned so far plus what you reasonably expect to earn for the rest of the year, minus certain deductions the tax code allows you to subtract before arriving at adjusted gross income.
Getting the number right matters. A low estimate on a Marketplace application can leave you owing back thousands in premium subsidies at tax time. A low estimate on quarterly tax payments can trigger an underpayment penalty. The sections below walk through what belongs in the figure, what does not, and how to arrive at a defensible number.
Income That Belongs in the Estimate
Federal law defines gross income broadly. It covers earnings from essentially every source unless a specific statute excludes them.1Office of the Law Revision Counsel. 26 USC 61 – Gross Income Defined When building your estimate, add up every source that applies to you:
- Wages, salaries, tips, bonuses, and commissions from employers.
- Self-employment revenue minus ordinary and necessary business expenses.2Internal Revenue Service. Self-Employed Individuals Tax Center
- Interest, dividends, capital gains, rental income, and royalties.
- Pensions, annuities, and withdrawals from traditional retirement accounts.
- Taxable portions of Social Security benefits, unemployment compensation, alimony received under pre-2019 agreements, and gambling winnings.
Gross income includes money, property, and services you receive unless a statute specifically excludes them.3eCFR. 26 CFR 1.61-1 – Gross Income If you have several income streams, each one adds to the total.
Income to Leave Out
Several common types of money are excluded from gross income under federal law. Adding them would inflate your estimate and could disqualify you from benefits you are entitled to.4Internal Revenue Service. Publication 525 (2025), Taxable and Nontaxable Income Do not include:
- Child support you receive.
- Gifts and inheritances (though any interest, dividends, or rent the property later produces is taxable).
- Life insurance death benefits paid to you as a beneficiary.
- VA disability compensation, pension payments, and education allowances.
- Workers’ compensation for a work-related injury or illness.
- Supplemental Security Income (SSI).
- Compensatory damages for personal physical injury or sickness.
One boundary worth noting: the Marketplace uses a slightly broader definition than the IRS. Some items that stay out of gross income get added back for MAGI, covered below.
Calculating the Number in Three Steps
The core calculation is straightforward. Total what you have earned year to date, project what you expect to earn for the rest of the year, then subtract above-the-line deductions to get your adjusted gross income.
Step 1: Total year-to-date income. Pull your most recent pay stubs, bank and brokerage statements, and any 1099s already received. Add up every taxable source from the list above.
Step 2: Project the rest of the year. If your income is steady, multiply average monthly earnings by the months remaining. Factor in known changes: a raise, a bonus, seasonal work, or a client you have already lost or gained. Self-employed people should compare against the same period in prior years and adjust for current volume and pricing.
Step 3: Subtract above-the-line deductions. These reduce gross income before you reach AGI. Common ones for 2026:
- Up to $2,500 of student loan interest, subject to income phase-outs.5Internal Revenue Service. Topic No. 456, Student Loan Interest Deduction
- Traditional IRA contributions up to $7,500, or $8,600 if you are 50 or older; deductibility may be limited if you or your spouse have a workplace retirement plan.6Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
- HSA contributions up to $4,400 with self-only coverage or $8,750 with family coverage.7Internal Revenue Service. Notice 2026-05, HSA Inflation Adjusted Amounts
- Half of self-employment tax, if you are self-employed.
The result is your estimated AGI. Most federal programs, the IRS, and most lenders start with this figure.
MAGI: The Version the Marketplace Uses
For Health Insurance Marketplace applications, the operative number is modified adjusted gross income, not AGI. MAGI starts with AGI and adds back three items: untaxed foreign income, nontaxable Social Security benefits, and tax-exempt interest.8HealthCare.gov. Modified Adjusted Gross Income (MAGI) MAGI does not appear as its own line on your tax return, so you calculate it yourself.
The Marketplace uses your expected household MAGI for the coverage year, not last year’s income, to determine premium tax credits and cost-sharing reductions.9HealthCare.gov. What’s Included as Income If you have tax-exempt bond interest or nontaxable Social Security, those amounts push MAGI above AGI and can change the size of your subsidy.
Where the Estimate Gets Used
Health Insurance Marketplace Subsidies
Your estimated household income determines whether you qualify for the premium tax credit that lowers your monthly premium. For 2026, eligibility generally requires household income between 100% and 400% of the federal poverty level for your family size.10Internal Revenue Service. Eligibility for the Premium Tax Credit The credit works on a sliding scale, with larger credits at lower incomes.11HealthCare.gov. Federal Poverty Level (FPL)
Understating your estimate carries real cost. If your actual income comes in higher than what you projected, you owe back some or all of the excess advance credit payments at tax time. For 2026, there is no cap on the repayment amount regardless of income level.12CMS: Agent and Brokers FAQ. Are There Limits to How Much Excess Advance Payments of the Premium Tax Credit (APTC) Consumers Must Pay Back If your income exceeds 400% of the federal poverty level, you lose eligibility entirely and must repay all advance credits received.10Internal Revenue Service. Eligibility for the Premium Tax Credit
Quarterly Estimated Tax Payments
If you have income without withholding, such as freelance earnings, investments, or rentals, you may need to make quarterly estimated tax payments using Form 1040-ES.13Internal Revenue Service. Estimated Taxes These payments are based on your projected annual income, deductions, and credits.
For 2026, the payments are due April 15, June 15, September 15, and January 15, 2027.14Internal Revenue Service. Pay as You Go, So You Won’t Owe You avoid an underpayment penalty if your total tax bill after withholding and refundable credits is under $1,000, or if you satisfy one of two safe harbors: pay at least 90% of your current-year tax, or pay at least 100% of the tax shown on your 2025 return (110% if your 2025 AGI exceeded $150,000, or $75,000 if married filing separately).15Internal Revenue Service. 2026 Form 1040-ES Estimated Tax for Individuals Falling short triggers penalty interest, set at 7% for the first quarter of 2026.16Internal Revenue Service. Quarterly Interest Rates
Loan and Credit Applications
Lenders use your estimated income to calculate your debt-to-income ratio and decide how much you can borrow. Mortgage underwriters, credit card issuers, and personal loan providers all rely on the figure. Overstating it can push you into debt you cannot service; understating it can produce a denial or a lower credit limit.
A Boundary: Federal Student Aid
The FAFSA is a common source of confusion here. The 2026–2027 FAFSA uses your 2024 tax return data, not a forward-looking estimate.17Federal Student Aid. 2026-27 FAFSA Form If your finances changed significantly after 2024, you can ask your school’s financial aid office for a special circumstances review, which may recalculate eligibility using more recent income.
Keeping the Estimate Current
An estimate is only useful if it reflects reality. When your income changes after you enroll in Marketplace coverage, you are expected to report the change within 30 days so the Marketplace can adjust your advance premium tax credit.18GovInfo. Report Life Changes When You Have Marketplace Coverage Report late if you have to, but report.
The stakes are higher in 2026 than they were recently. In 2025, a single filer with household income under 200% of the federal poverty level only had to repay up to $375 in excess advance credits. For 2026, that cap is gone: every excess dollar comes back regardless of income.12CMS: Agent and Brokers FAQ. Are There Limits to How Much Excess Advance Payments of the Premium Tax Credit (APTC) Consumers Must Pay Back The same principle applies to quarterly estimated taxes: if your income spikes mid-year, adjust upcoming payments rather than absorbing a penalty in April.
Keep the pay stubs, statements, 1099s, and worksheets you used to build the estimate. If the IRS or the Marketplace ever questions the number, those records are how you show your work.