About CalcWorthy

CalcWorthy is an independent website that publishes free online calculators. Our goal is simple: give you a correct answer in seconds and show you how that answer was reached, so you can trust it and make better decisions.

How we build our calculators

• Standard, published formulas. Loan payments use the standard amortization formula, health calculators use the formulas published in the medical literature (for example Mifflin-St Jeor for calorie needs and the U.S. Navy method for body fat), and date tools follow the Gregorian calendar including leap years.
• Tested against known values. Every calculator is checked automatically against independently known results each time the site is built. If a check fails, the site is not published.
• The formula is always shown. Each page explains the method, walks through an example and answers common questions.
• Private by design. Calculations run entirely in your browser. The numbers you type are never sent to our servers.

Free to use

All calculators are free and require no account. The site is supported by advertising, which pays for hosting and development.

Corrections and suggestions

If you spot an error or want a calculator we don't have yet, please contact us. We review every message and fix confirmed errors quickly.