Free online calculators
Finance, health, utility and construction calculators — fast, accurate and free.
Calculivo is a free collection of online calculators for everyday financial, health, utility and construction questions. Every tool runs entirely in your browser — no sign-up, no app, no data sent to a server.
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About Calculivo
We focus on the calculations people actually search for: mortgage payments, compound interest growth, VAT and sales tax, salary conversions, BMI, daily calorie needs, paint estimates, and dozens more. Each calculator is hand-written, the formulas are documented on the page, and worked examples show exactly what the math is doing.
Calculivo is available in English, German, French and Spanish, with country-specific variants where it matters — three separate VAT pages for German rates, three for French, three for Spanish, plus real net-pay calculators using each country's 2025 income-tax brackets and social-insurance rules. The site is built on Astro as static HTML, loads in under a second on Core Web Vitals, and supports both dark and light themes.
Use the categories below to browse by area, or jump straight to one of the most-visited calculators. For longer explainers — how compound interest actually works, what BMI categories mean, why your salary slip looks the way it does — see our guides section.