Calculate US federal income tax
A tax calculator estimates your federal income tax based on income, filing status, and deductions. Understanding how tax brackets work helps with financial planning and ensures you're not surprised at tax time. This calculator uses 2024 US federal tax brackets.
Tax is calculated progressively through each bracket
Marginal tax rate is the rate on your last dollar of income (your tax bracket). Effective tax rate is total tax paid divided by total income. Example: $100,000 income might have 22% marginal rate but only 15% effective rate because lower brackets are taxed at 10% and 12% first.
Tax brackets are progressive - you pay different rates on different portions of income. Only income WITHIN each bracket is taxed at that rate. Earning $50,000 doesn't mean all $50,000 is taxed at 22%. The first $11,600 is taxed at 10%, next $35,550 at 12%, remaining at 22%.
Take whichever is larger. Standard deduction for 2024: $14,600 (single), $29,200 (married). Itemize if your mortgage interest, state/local taxes (SALT, capped at $10,000), charitable donations, and medical expenses exceed the standard deduction. Most taxpayers benefit from the standard deduction.
Contribute to pre-tax accounts: 401(k), traditional IRA, HSA. These reduce taxable income directly. Max out employer retirement match. Time income and deductions strategically. Harvest tax losses. Use tax credits (child, education, energy). Consider Roth conversions in low-income years.
Deductions reduce taxable income (saving your marginal rate on that amount). Credits reduce tax dollar-for-dollar. A $1,000 credit saves $1,000 in taxes. A $1,000 deduction at 22% bracket saves only $220. Credits are more valuable. Common credits: Child Tax Credit, Earned Income Credit, education credits.
If you owe $1,000+ at tax time, you may need quarterly estimated payments. This typically affects self-employed, freelancers, and those with significant investment income. Use Form 1040-ES. Missing payments incurs penalties. Safe harbor: pay 100% of last year's tax (110% if high income) to avoid penalties.