Estimate your US federal income tax and your refund or amount owed for a chosen tax year using wages, other income, deductions, credits, and withholding. This calculator shows the full step-by-step breakdown so you can see how income turns into taxable income and then into tax.
Advanced options
How to use our Income Tax Calculator
- Select the tax year and your filing status.
- Enter your annual W-2 wages (job income) and any other taxable income.
- Enter your total federal withholding plus any estimated tax payments for the year.
- Open Advanced options and enter adjustments that reduce income (if you have them) to get a better AGI estimate.
- Choose a deduction type: Standard deduction (uses the tax-year amount) or Itemized (enter your total itemized deductions).
- Enter nonrefundable credits (they can reduce income tax to 0) and refundable credits (they can increase your refund) if you want to include them.
- If you want to estimate total tax burden (not just income tax), turn on payroll taxes and optionally add self-employment net income.
- If you want an NIIT estimate, enter both net investment income and modified AGI for the NIIT test (enter neither to skip).
- Click Calculate, then compare the results cards to your expectations: AGI, deduction used, taxable income, income tax, total tax after credits, and refund or owed.
Definitions
Total income (simplified): W-2 wages plus other taxable income, plus optional self-employment net income.
Adjustments that reduce income: Amounts that lower adjusted gross income (AGI), such as some IRA, HSA, or student loan interest deductions (entered as one total here).
Adjusted gross income (AGI): Total income minus adjustments (simplified). Many tax rules start from AGI.
Deduction (standard or itemized): An amount subtracted from AGI to get taxable income. Standard deduction amounts depend on tax year and filing status [1].
Taxable income: AGI minus deductions, not below 0. Tax brackets apply to this number.
Federal income tax (from brackets): The progressive tax computed from taxable income and the tax bracket schedule.
Marginal tax rate: The bracket rate on your next dollar of taxable income.
Effective tax rate: Federal income tax divided by total income (simplified overall percentage).
Nonrefundable credit: A credit that can reduce income tax down to 0, but usually not below 0 (simplified).
Refundable credit: A credit that can still benefit you even if your income tax is 0, and can increase a refund (simplified) [3].
Withholding and estimated payments: Federal tax already paid during the year through paycheck withholding and/or estimated payments [2].
Refund or amount owed: Your payments minus your total tax after credits. Positive means refund; negative means you may owe.
Methodology
What this calculator includes
This is a simplified return-style estimator for US federal taxes. It estimates federal income tax from brackets, then applies credits, then compares the result to your withholding and estimated payments [2]. It can also optionally add payroll taxes and NIIT as separate add-ons, but those are not part of Form 1040 income tax.
Step 1: Add up income and compute AGI
AGI = max(0, wages + other_income + self_employment_income - adjustments_pre_tax)
AGI is floored at 0 in this simplified model.
Step 2: Choose the deduction and compute taxable income
deduction_used = (deduction_type == "Standard") ? standard_deduction(tax_year, filing_status) : itemized_deductions
For 2026 standard deduction amounts, the calculator uses the IRS inflation-adjusted figures by filing status [1]. If you select Itemized, you must enter your itemized total.
taxable_income = max(0, AGI - deduction_used)
Step 3: Compute federal income tax from brackets
federal_income_tax = progressive_tax(taxable_income, bracket_thresholds, bracket_rates)
The progressive tax function taxes each slice of taxable income at the matching marginal rate, then adds the slices.
Step 4: Apply credits (simplified)
income_tax_after_nonrefundable = max(0, federal_income_tax - tax_credits)
Nonrefundable credits are floored at 0 in this simplified model. Refundable credits can increase a refund (simplified) [3].
Step 5 (optional): Add payroll taxes and NIIT
ss_tax = 0.062 * min(wages, ss_wage_base)
medicare_tax = 0.0145 * wages
se_tax = 0.153 * self_employment_income
Self-employment income is only used when payroll taxes are turned on, so you do not accidentally mix income tax and payroll tax.
niit = 0.038 * min(net_investment_income, max(0, modified_agi - niit_threshold(filing_status)))
NIIT is computed only when both net investment income and modified AGI are provided; otherwise NIIT shows N/A.
Step 6: Total tax after credits, then refund or owed
total_tax_after_credits = income_tax_after_nonrefundable + optional_payroll_and_surtaxes - refundable_credits
refund_or_owed = withholding_and_payments - total_tax_after_credits
Withholding and estimated payments are treated as already-paid federal tax for the year [2]. If refund_or_owed is positive, that is the refund estimate; if negative, that is the amount owed estimate (before any penalties or interest).