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Work out a loan payment, estimate your US federal income tax, see how your savings could grow, or check the margin on a product. All 38 calculators explain how the result is worked out.
Start here
Not sure where to begin? Try one of these six.
Monthly payment, total interest and yearly balance on a fixed-rate loan
2026 federal income tax from the IRS brackets for your filing status
How a single deposit grows at any interest rate and compounding frequency
What saving a set amount each month could add up to by retirement
Convert between world currencies using daily reference rates
Gross margin from cost and price, or the price for a target margin
All calculators
All 38 calculators, grouped by what you're trying to work out.
12 calculators
Growth of lump sums and monthly investing, deposits and retirement savings, returns on funds and shares, and the effect of inflation.
7 calculators
Pricing and costs for a business: margin, markup, break-even point, revenue and costs, and adding or removing GST or VAT.
6 calculators
Take-home pay and federal income tax for US earners, hourly rates, savings goals, net worth and splitting a bill.
6 calculators
Mortgage and loan payments, whether renting or buying comes out ahead, paying off debt faster, and how your debts compare with your income.
3 calculators
Plan and review trades in shares, crypto and more: profit or loss after fees, position size from your risk, and risk-reward.
4 calculators
Quick everyday sums: percentages, discounts, simple interest, and currency conversion at daily reference rates.
The tools page lists the same calculators with a one-line summary of each.
Three steps
Search or browse by category. Each calculator answers one question, such as a monthly payment or a tax estimate.
Results update as you type. If a value can't work, such as a negative loan amount, a message explains why.
Check the totals, then see how the figure was worked out and what the calculation does and doesn't include.
Transparency
Every calculator explains how its result is calculated, so you can check the math yourself.
Where a result depends on compounding, fees or what a tax estimate leaves out, the calculator page says so.
The income tax calculator uses the brackets and standard deductions the IRS publishes for the tax year shown on its page.
Calculations run in your browser. The amounts you enter aren't sent to us or saved.
Use them as a starting point for your own decisions.
Read the disclaimer and privacy policy for the details. Spotted a mistake or missing a calculator? Get in touch, or read more about FinCalcBox.
Further reading
Longer explanations of the ideas behind some of the calculators.
How compound interest works, with worked examples: why time matters most, how compounding frequency, fees, inflation and taxes affect growth, and why it works against you on debt.
How to judge a fund's performance: benchmarks, total return, fees, volatility, drawdown, the Sharpe ratio, alpha and beta, with worked examples. For mutual funds, unit trusts, OEICs and managed funds.