About

Most of the time you want one number. What will this loan cost me a month. What will my savings be worth in twenty years. What percent of 200 is 30. Getting that usually means a login, a lead form, or building a spreadsheet yourself.

So this site is three calculators and nothing else.

How it works

Plain HTML, CSS and JavaScript. You type a number, your browser does the arithmetic, the answer appears. No server does the calculation. Nothing you enter is saved or sent anywhere. There is no account and nothing to install.

The formulas

The loan calculator uses payment = P × i × (1+i)^n / ((1+i)^n − 1) and then builds the schedule month by month, charging interest on whatever is still owed. The compound interest calculator compounds monthly and treats deposits as end-of-month. Each formula is written out on the calculator that uses it, so you can check the answers against your own working. That seems fair for a calculator you did not write yourself.

What it is not

It is not financial advice. It does not know your fees, your taxes, your insurance, or how your lender rounds. Treat the numbers as good estimates and confirm the important ones.

If a result looks wrong, tell me. Corrections are welcome.