Income Tax Calculator

Estimate your federal income tax, taxable income, effective tax rate, marginal tax rate, and after-tax income. This free income tax calculator is a simple planning tool for common filing situations.

Results

Taxable Income
$0
Federal Income Tax
$0
State Income Tax
$0
Total Estimated Tax
$0
Effective Tax Rate
0%
After-Tax Income
$0
Marginal Tax Rate
0%
Deduction Used
$0
Adjusted Gross Income
$0

Enter your values and click Calculate to estimate your income taxes.

How this income tax calculator works

This income tax calculator estimates federal income tax by starting with annual gross income, subtracting pre-tax adjustments, then applying either a standard deduction or itemized deductions to reach taxable income.

It then applies progressive federal tax brackets to estimate federal tax, subtracts any entered tax credits, and optionally estimates state income tax using a flat percentage rate. The results show taxable income, total estimated tax, effective tax rate, and after-tax income.

What to enter

  • Your annual gross income
  • Your filing status
  • Whether you use the standard or itemized deduction
  • Your itemized deductions if applicable
  • Any pre-tax retirement contributions
  • Other adjustments to income
  • Any tax credits
  • An optional flat state tax rate

What the results mean

  • Taxable Income: income remaining after deductions
  • Federal Income Tax: estimated federal tax after credits
  • State Income Tax: estimated state tax using the flat state rate entered
  • Total Estimated Tax: combined federal and state estimate
  • Effective Tax Rate: total tax as a percentage of gross income
  • Marginal Tax Rate: tax rate applied to your top bracket of taxable income
  • After-Tax Income: estimated remaining income after taxes

Income tax calculator formula

This calculator uses a simplified tax-planning method:

Adjusted Gross Income = Gross Income - Pre-Tax Adjustments
Taxable Income = Adjusted Gross Income - Deduction

Federal income tax is then calculated progressively through tax brackets, meaning different portions of taxable income are taxed at different rates.

Effective tax rate is estimated with:

Effective Tax Rate = Total Tax ÷ Gross Income

Tips for using an income tax calculator

Know the difference between marginal and effective tax rates

Your marginal rate applies to the highest portion of your taxable income, while your effective rate reflects your total tax burden across all brackets.

Use deductions carefully

Some taxpayers benefit more from the standard deduction, while others benefit from itemizing. Comparing both can be useful for planning.

Tax credits reduce tax directly

Credits typically reduce your tax bill dollar for dollar, while deductions reduce taxable income before tax is calculated.

Use this as a planning estimate

Real tax returns can include many additional rules, phaseouts, surtaxes, payroll taxes, and state-specific details not included here.

Frequently asked questions

Does this calculator include payroll taxes?

No. This calculator estimates income tax only. Social Security and Medicare payroll taxes are not included in this version.

Does this calculator include every federal tax rule?

No. This is a simplified planning tool. It does not include every tax credit, deduction limit, phaseout, or special rule.

Can I use itemized deductions instead of the standard deduction?

Yes. This calculator lets you switch between a standard deduction and a custom itemized deduction amount.

Is the state tax estimate exact?

No. The state tax estimate in this version uses a flat rate that you enter. Actual state tax systems may be more complex.

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