Income Tax Calculator

An income tax calculator estimates how much of your annual gross income you will owe to the federal government, your state, and your local government — and how much you will take home after all taxes. It applies the actual 2024 IRS tax brackets progressively, accounts for pre-tax deductions (401(k), HSA, FSA) that reduce your taxable income, computes FICA payroll taxes (Social Security and Medicare), and divides the result by your pay frequency to show the per-paycheck impact.

The key insight this calculator surfaces is the difference between your marginal tax rate and your effective tax rate. Your marginal rate is the rate applied to the last dollar you earn — the highest bracket you reach. Your effective rate is the actual percentage of your total income paid in federal tax, which is always lower because each bracket only applies to the income within that bracket range, not your full income.

This calculator covers W-2 wage earners — employees who receive a regular paycheck with taxes withheld. It does not model self-employment tax (15.3% on self-employment income), alternative minimum tax (AMT), estimated quarterly tax payments, or income phaseouts for specific deductions. For complex tax situations, use this as a starting estimate and consult a CPA or enrolled agent.

Disclaimer: This calculator provides estimates for the 2024 tax year using federal brackets and simplified state flat rates. Actual tax liability depends on additional factors not modeled here. Consult a qualified tax professional for precise calculations.

The calculator follows the exact IRS process — five steps from gross income to take-home pay:

Worked example (Single filer, $85,000 gross, 5% state rate): Pre-tax 401(k) = $8,500 → AGI = $76,500. Standard deduction = $14,600 → Taxable income = $61,900. Federal tax = $1,160 (10%) + $4,266 (12%) + $3,245.50 (22%) = $8,671. Social Security = $5,270. Medicare = $1,233. State = $3,095. Total tax = $18,269. Effective total rate = 21.5%. Annual take-home = $66,731. Bi-weekly paycheck = $2,574.

FICA (Federal Insurance Contributions Act) taxes fund Social Security and Medicare — the two largest federal entitlement programs. Unlike income tax, FICA is not progressive and does not depend on your filing status or deductions. It is calculated directly on gross wages before any deductions.

The Additional Medicare Tax (0.9%) applies to wages above $200,000 for single filers and $250,000 for married filing jointly. Importantly, employers only withhold this tax once wages exceed $200,000 for any individual employee — if you and your spouse each earn $150,000 ($300,000 combined MFJ), your employers may not withhold the Additional Medicare Tax during the year, and you would owe it when filing. This is a common source of unexpected tax bills for dual-income married couples.

Self-employed individuals pay both sides of FICA — the full 15.3% (12.4% Social Security + 2.9% Medicare) plus the 0.9% Additional Medicare Tax on income above the threshold. However, they can deduct the employer-equivalent half (7.65%) as an above-the-line adjustment to income, partially offsetting the higher rate.

A deduction reduces your taxable income — it is worth your marginal tax rate on each dollar deducted. At a 22% marginal rate, a $1,000 deduction saves $220 in federal income tax. There are two categories:

State income tax varies significantly — from 0% in nine states to over 13% at the top bracket in California. Use the values below to set the state rate slider for your location.

The U.S. federal income tax system is progressive — income is divided into brackets, and each bracket rate applies only to the income within that range, not to your total income. Your marginal rate is the rate on the last dollar you earned (the highest bracket you reach). Your effective rate is total federal income tax divided by total gross income — always lower than your marginal rate.

Example: A single filer earning $85,000 in taxable income (after deductions) in 2024 has a marginal rate of 22%. But the effective rate is much lower: the first $11,600 is taxed at 10% ($1,160), the next $35,550 at 12% ($4,266), and only $37,850 at 22% ($8,327) — total = $13,753 on $85,000 = 16.2% effective rate. Saying “I'm in the 22% bracket” does not mean you pay 22% of your income in federal tax.

The Tax Cuts and Jobs Act (TCJA) and 2026: The current bracket structure, standard deduction amounts, and the $10,000 SALT cap were created by the TCJA enacted in December 2017. These provisions are scheduled to sunset (expire) after December 31, 2025, reverting to pre-2018 law — which had higher rates, lower standard deductions, and no SALT cap — unless Congress acts to extend them. Tax planning for 2026 and beyond should account for this uncertainty.

Tax credits vs. tax deductions: A deduction reduces taxable income — its value is your marginal rate times the deduction amount. A tax credit reduces your tax owed dollar-for-dollar, making it generally more valuable. A $1,000 credit is worth exactly $1,000 in tax savings regardless of your bracket; a $1,000 deduction is worth only $220 at a 22% rate. Common credits include the Child Tax Credit ($2,000/child), the Earned Income Tax Credit (EITC), the Child and Dependent Care Credit, the American Opportunity Tax Credit for education, and the Saver's Credit for retirement contributions.