About us

CalculatorHandy is a collection of free online calculators for everyday decisions: money, health, study, dates, home projects and unit conversions. We built it because many calculators online give a number without explaining where it came from.

How we build the calculators

• Documented formulas. Each calculator uses a standard, published method and explains it on the page, with the assumptions it makes.
• Visible working. Results come with step-by-step working so you can follow and verify them.
• Tested against worked examples. Calculations are checked against known results before they are published, and the examples on each page come from the calculator itself.
• Private by design. The calculations run in your browser. We do not collect the numbers you enter.

What the calculators are not

They are tools for estimating, planning and learning. They are not a substitute for advice from a qualified financial adviser, tax professional, doctor or lawyer. Please read our Disclaimer.

Found a mistake?

If a result looks wrong, tell us which calculator you used, what you entered and what you expected. We read every message. Write to us via the Contact page.