US federal income tax is progressive: each slice of taxable income is taxed at its own rate. The highest rate that touches your last dollar is your marginal rate. The share of your gross income that you actually pay in federal income tax is your effective rate. Confusing those two numbers leads people to overestimate how painful a raise or side job will be.
All 2026 dollar amounts below come from IRS Revenue Procedure 2025-32, the same source our income tax calculator uses.
What a marginal bracket is — and is not
A bracket is a range of taxable income paired with a rate. For a single filer in 2026 the ordinary-income brackets begin:
- 10% on taxable income from $0 to $12,400
- 12% on the next slice through $50,400
- 22% through $105,700
- 24% through $201,775
- 32% through $256,225
- 35% through $640,600
- 37% above that
Only the dollars inside a bracket get that bracket’s rate. Crossing into the 22% bracket does not re-tax your earlier income at 22%. A $1,000 raise that sits entirely in the 22% bracket costs about $220 in federal income tax before payroll taxes and deductions — not 22% of your whole salary.
Married filing jointly uses wider brackets (for example, the 10% bracket runs through $24,800). Head of household and married filing separately have their own tables in the same revenue procedure.
Effective rate versus marginal rate
Take a single filer with $85,000 of gross income, $5,000 of traditional 401(k) contributions and the standard deduction. Taxable income is $85,000 − $5,000 − $16,100 = $63,900.
Federal income tax on that amount is $8,770:
- 10% on the first $12,400 → $1,240
- 12% on the next $38,000 → $4,560
- 22% on the remaining $13,500 → $2,970
The marginal rate is 22%. The effective rate (tax ÷ gross) is about 10.3%. That gap is normal. Planning decisions like “should I contribute more to a traditional 401(k)?” use the marginal rate; “what share of my income went to federal income tax?” uses the effective rate.
Standard deduction versus itemizing
Before brackets apply, you subtract deductions from adjusted income. For 2026 the standard deduction under Rev. Proc. 2025-32 §4.14 is:
- Single or married filing separately: $16,100
- Married filing jointly: $32,200
- Head of household: $24,150
You itemize only when Schedule A deductions (mortgage interest, state and local taxes within the cap, charitable gifts, and other allowed items) exceed that standard amount. Our calculator automatically uses whichever is larger when you enter an itemized total.
Example: married filers with $120,000 gross, $10,000 pre-tax deductions and $28,000 of itemized deductions still take the $32,200 standard deduction because it is larger. Taxable income is $77,800 and tax is $8,840. Raise itemized deductions to $35,000 and the calculator switches to itemizing; taxable income falls to $75,000 and tax to $8,504.
How brackets are adjusted for inflation
Each year the IRS publishes inflation adjustments so bracket thresholds and the standard deduction keep pace with prices. Rev. Proc. 2025-32 is the adjustment package for tax year 2026. Using last year’s thresholds with this year’s income will misstate your tax. When you estimate 2026 liability, use 2026 figures — which is what the income tax calculator is built on.
What this estimate leaves out
The calculator models ordinary federal income tax after pre-tax deductions and the larger of the standard or itemized deduction. It does not apply credits (Child Tax Credit, education credits and others), capital gains rates, self-employment tax, Alternative Minimum Tax or state tax. For take-home pay including FICA and state withholding, use the paycheck calculator.
Run your own numbers
Enter your filing status, gross income, pre-tax deductions and any itemized total in the income tax calculator. Read the marginal rate, effective rate and bracket breakdown together. If you are deciding between the standard deduction and itemizing, try both itemized totals and watch which deduction type the result uses. For paycheck-level planning after FICA and state tax, switch to the paycheck calculator.
Raises, side income and bracket myths
A common fear is that a raise will “push you into a higher bracket” and shrink take-home pay overall. That does not happen with a progressive tax. Only the dollars above the threshold are taxed at the new rate. You can still owe more tax in total — and FICA still applies — but your after-tax income rises with the raise unless a benefit cliff or contribution limit elsewhere intervenes.
Side income reported on a 1099 is different: it may trigger quarterly estimated taxes and self-employment tax, which this calculator does not model. Use the bracket view for W-2 ordinary income planning, then talk to a tax professional if you are self-employed.
Knowing your bracket matters. Knowing that only the next dollar is taxed at that bracket matters more.