Money Calculators
Five free tools for the money math of everyday life — each one instant, mobile-friendly, and paired with a plain-English explanation of how the numbers work.
Not sure where to start?
Most everyday questions are percentage questions in disguise. Start there, or browse the guides to learn each formula step by step.
Good to know
About these calculators
Every calculator on this page runs entirely in your browser — your numbers never leave your device. There are no accounts, no paywalls, and no “download our app” gates between you and an answer.
Each tool also teaches: below every calculator you’ll find the formula, worked examples, and answers to the questions people ask most. The goal is that each use makes the next decision a little easier.
Calculators provide general educational information and estimates. They don’t know your full situation and can’t replace professional advice for tax, legal, or investment decisions — see our financial disclaimer.
Educational information only. For educational and informational purposes only. This website does not provide personalized financial, investment, tax, or legal advice.
Are these calculators free?
Yes. All five calculators are completely free with no account, no sign-up, and no usage limits. They run instantly in your browser, including on phones.
Which calculator should I use for sale prices?
Use the Discount Calculator for percent-off sales (it includes a compare-two-deals helper), and the Sales Tax Calculator to add tax to the discounted price.
How accurate are the results?
Results are mathematically exact for the numbers you enter, rounded to the nearest cent. Compound-interest projections are estimates that assume a constant rate and ignore fees, taxes, and inflation.
Do you store what I calculate?
No. Calculations happen locally in your browser. We don’t ask for personal financial details, and the calculators don’t transmit your inputs anywhere.