About CalcMate
Hi, I am Mihail Doncenco. I built CalcMate and I maintain it myself. I have worked in tech for more than 15 years as a developer and SEO specialist. I started this site because I wanted calculators without paywalls or cluttered pages, where you can see how the answer was reached.
CalcMate has over 100 calculators for math, finance, health, physics and unit conversion, available in 9 languages: English, German, Spanish, Portuguese, Turkish, Indonesian, Italian, French and Vietnamese. Rules for loans, taxes and salaries differ from country to country, so the calculators that depend on them say which country's rules they use.
Where the formulas come from
I do not make up formulas. Each calculator is built from a published method and checked against known examples before it goes live. Some examples:
- Health. Calorie needs use the Mifflin-St Jeor equation (1990). BMI categories follow WHO thresholds. I chose Mifflin-St Jeor after reading a 2005 review in the Journal of the American Dietetic Association, which found it the most reliable of the common equations on average.
- Physics. Constants come from the CODATA 2022 values published by NIST.
- Unit converters. Conversion factors come from NIST Special Publication 1038 and the SI Brochure (9th edition, 2019) from the BIPM.
- Loans and mortgages. Payments use the standard annuity formula M = P × r(1+r)n / ((1+r)n − 1). Some countries have their own rules for how loan costs must be shown, such as PAngV in Germany, EU Directive 2008/48/EC and the CET method in Brazil. The calculator for that country is built around them.
- Taxes and salaries. Figures come from official government publications. Every calculator page shows the date it was last updated, so you can see how current it is.
Your data, independence and corrections
Your data stays with you. Calculations run in your browser with JavaScript. When you press Calculate, the numbers you typed are not sent to our server and we do not store them. You can check this yourself: open your browser developer tools (F12), go to the Network tab and run a calculation.
Independence and limits. CalcMate does not take payment to feature particular financial products, tax strategies or health advice. Results come from the formulas and nothing else. A calculator gives an estimate based on what you enter. For decisions about your health, taxes, loans or legal matters, check the result with a qualified professional. I am a developer, not a doctor, accountant or lawyer, and the calculators say so where it matters.
Found a mistake? Formulas and rules change, and I can get things wrong. If you spot an error, a missing rule for your country, or want a calculator that does not exist yet, write to [email protected]. I read these messages myself. When I fix something, the Last updated date on that calculator page changes.