Free · No sign-up · Formulas explained
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 financial calculators are free and 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 lump sum grows, with optional regular deposits, at any rate and compounding frequency
What saving each month could add up to by retirement, and how long it could last
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.
6 calculators
Take-home pay and federal income tax for US earners, hourly rates, savings goals, net worth and splitting a bill.
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
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.
Coverage
These financial calculators are for anyone checking a money decision: a household comparing loans, a saver planning a goal, a small business pricing a product or a trader sizing a position. Only the tools built on tax rules are tied to one country, and each says so on its page.
Loans, mortgages, compound interest, savings, investment returns, percentages, business pricing and trading calculators use plain math. Enter amounts in your own currency and the results hold wherever you live.
The income tax calculator uses the IRS federal brackets and standard deductions for 2026. The salary calculator adds Social Security and Medicare; state tax is a rate you enter.
The VAT calculator has the UK's 20% and 5% rates built in. The GST calculator has rates for Australia, New Zealand, Canada (GST or HST) and Singapore. Both accept any other rate.
The currency converter uses daily reference rates, not live market prices, so check with your bank or provider before you exchange money.
Questions
A financial calculator works out money questions that take several steps by hand, such as a monthly loan payment, how savings grow with compound interest or the tax on an income. Each calculator on FinCalcBox answers one question and shows how the figure was reached.
The math in each calculator is tested against worked examples and rounded to the cent, but a result is only as good as the numbers and assumptions behind it. Every calculator page lists what it assumes and what it leaves out, such as fees, state taxes or future rate changes. Treat the results as estimates, not financial, tax or legal advice.
Every calculator is free and there's nothing to sign up for. The amounts you enter are worked out in your browser and aren't sent to us or saved.
Most calculators are plain math, so they work in any country and any currency. The ones built on tax rules say which country they cover: income tax and take-home pay use US federal rules for 2026, the VAT calculator has the UK rates built in, and the GST calculator has rates for Australia, New Zealand, Canada and Singapore.
These are Indian names for common products: a fixed deposit (FD) is what the US calls a CD, Canada a GIC and Australia a term deposit, and an EMI is a fixed monthly loan repayment. A recurring deposit (RD) and a SIP are both regular monthly saving or investing. The math works the same wherever you are.
Further reading
Longer explanations of the ideas behind some of the calculators.
A step-by-step break-even walkthrough for a small candle business: fixed and variable costs, contribution margin, break-even in units and revenue, a profit target, and which lever moves the number most.
Taking 20% off a VAT-inclusive price doesn't give you the price before VAT. Learn the divide method and the tax-fraction shortcut, with worked examples for the UK, Australia and Canada.
Markup and margin use the same profit but divide it by different numbers. See the formulas, a conversion table, pricing to a target margin and the mistakes that quietly cost sellers money.