Free Tax Tools & Calculators
All our calculators are free to use, updated for the 2025 tax year, and use IRS-accurate data. No signup, no email required — just enter your numbers and get instant results.
401k Calculator
Project your 401k retirement savings growth. See how much your contributions + employer match can grow with compound interest.
Try it freeCapital Gains Calculator
Calculate capital gains tax on stocks, real estate, and investments. Includes short-term and long-term rates plus NIIT.
Try it freeAmortization Calculator
Full loan amortization schedule. See monthly payments, total interest, and year-by-year principal/interest breakdown.
Try it freeLoan Payment Calculator
Calculate monthly loan payments, total interest, and total cost for mortgages, auto loans, and personal loans.
Try it freeMargin Calculator
Calculate gross profit margin and markup for your products. Essential for small business pricing decisions.
Try it freePaycheck Calculator
Calculate your 2025 take-home pay after federal and state taxes. Supports NY, TX, CA, and all states.
Try it freeTax Bracket Calculator
Find your 2025 federal tax bracket. See marginal rates, effective tax rate, and total tax owed by filing status.
Try it freeRefund Tracker
Estimate your IRS refund timeline. See when to expect your tax refund based on filing method and deposit type.
Try it freeW-4 Estimator
Estimate your 2025 federal withholding. Check if you're on track for a refund or if you need to adjust your W-4.
Try it freeSales Tax Calculator
Calculate sales tax for any US state. Enter a price and select a state to see the tax amount and total. Includes all 50 states with 2025 rates.
Try it freeFrequently Asked Questions About Tax Calculators
Are these tax calculators accurate?
Yes. Our calculators use IRS tax tables and rates for the 2025 tax year. They provide estimates — for your exact tax situation, consult a tax professional or use IRS filing software.
Do I need to sign up or create an account?
Not at all. All SupaTax.ai calculators are completely free with no signup required. Just enter your numbers and get instant results.
What tax year are these calculators for?
All calculators are updated for the 2025 tax year (returns filed in 2026). This includes 2025 federal income tax brackets, standard deductions, and FICA rates.