Taxable income is the part of your income left after eligible adjustments and deductions, which the government uses to calculate income tax. It is usually less than your total earnings. On a federal return, start with adjusted gross income (AGI), then subtract the standard or itemized deduction and other allowed deductions. Credits reduce the resulting tax, not taxable income.
What is taxable income?
Think of taxable income as a calculation, not a number to copy from your paycheck. Salary is one input. Interest, dividends, business income, and taxable retirement distributions may also count. Some income is excluded, and eligible adjustments and deductions reduce what remains.
The IRS guide to figuring your tax describes the calculation. Use the Form 1040 and instructions for the year you are filing; line numbers can change.
How is taxable income different from AGI and from W-2 box 1?
| Amount | What it means |
|---|---|
| Gross income | Income included on your return before adjustments; not necessarily your total cash received |
| Adjusted gross income (AGI) | Gross income minus eligible adjustments, such as certain retirement contributions |
| Taxable income | AGI minus the standard or itemized deduction and other applicable deductions |
| W-2 box 1 | Taxable wages from one employer; it does not include all household income |
For example, assume a married couple filing jointly has $200,000 in W-2 box 1 wages and $20,000 in nonqualified dividends in 2026. They have no adjustments or other deductions and qualify for the basic joint standard deduction:
| Step | Amount |
|---|---|
| Wages plus dividends | $220,000 |
| AGI after $0 of adjustments | $220,000 |
| Subtract the 2026 joint standard deduction | −$32,200 |
| Taxable income | $187,800 |
The IRS 2026 inflation adjustments establish the $32,200 deduction. The $187,800 result is the income subject to the tax calculation, not the amount of tax owed.
A traditional 401(k) salary deferral is generally already excluded from W-2 box 1. Do not subtract it a second time when starting from that figure. The W-2 instructions explain what box 1 contains.
Which deductions reduce taxable income after AGI?
Most people use either the standard deduction or itemized deductions. Some also qualify for a qualified business income deduction or other deductions allowed for that tax year.
These deductions do not all reduce AGI. That distinction matters for benefits and taxes based on AGI or modified adjusted gross income (MAGI). A deduction can lower your regular income tax without changing an income-based eligibility test.
A tax credit works differently. If a permitted $2,000 deduction removes income that would all face a 22% federal rate, it saves $440 of federal income tax. A fully usable $2,000 tax credit reduces calculated tax by $2,000. Credits have their own eligibility and refundability rules; deductions and credits are not interchangeable.
Why does “is X taxable?” not name one line?
Ask what calculation you need the answer for. Federal income tax, state income tax, payroll tax, and benefit eligibility do not always count the same dollars.
For example, tax-exempt municipal bond interest is generally excluded from AGI, but it is added back when calculating income for Medicare premium surcharges. A taxable Roth conversion generally raises AGI and taxable income, but the Roth IRA contribution-eligibility calculation removes conversion income. Check the specific definition rather than treating every MAGI calculation as the same.
How do tax brackets use taxable income?
Ordinary income brackets apply to taxable income, not gross salary. Each bracket covers a slice of income. Moving into a higher bracket changes the rate on the next slice; it does not raise the rate on everything below it. Qualified dividends and long-term capital gains may use separate rates.
In the $187,800 joint-return example, the couple is below the 2026 24% ordinary-income bracket, which starts above $211,400. Using $220,000 of AGI as taxable income would put them in the wrong bracket when estimating tax on additional ordinary income.
How to estimate your own taxable income
Gather income from every source, subtract eligible adjustments, then compare the standard deduction with itemizing. Apply other deductions only if you qualify. Calculate tax and credits next, then compare the result with withholding and estimated payments. A refund or balance due measures that last comparison, not your taxable income.
For a wage-income estimate, start with a state income tax calculator. Its exclusions matter: a paycheck estimate does not replace a complete tax return.