About This Calculator

This Calculator is a collection of free online calculators. Each page does one job: it takes the numbers you type, applies one standard formula, and shows the answer together with the formula, the meaning of every variable and a worked example you can check by hand.

What you will find here

• Calculators in 14 subjects, from geometry and statistics to lumber, garden soil, running pace and data sizes. See the subjects or the full A to Z list.
• A unit converter for ten kinds of quantity, for when an input is in the wrong unit.
• The formula on every page, in words and symbols, and the exact lines the calculator runs in a “Formula used” box.

How the pages are made

Every calculator is built on a textbook formula. We keep to general, checkable arithmetic: no prices, rates, tax rules, medical or dosage advice, and nothing that depends on a law or a price list that changes. Where a topic needs a value only you can look up, the page says so and asks you to enter it. Read how the calculators work, including how results are rounded and what the limits are.

Who runs it

this-calculator.com is an independent site. It carries no advertising. It is not affiliated with any manufacturer, school or standards body, and no page claims official status.

Get in touch

Found a wrong result, a typo or a formula that does not fit the title? Please tell us on the contact page or by email at info@this-calculator.com. Fixes are listed on the corrections page.