Free, ad-supported calculators for construction, money, health and everyday math. No sign-up, no fluff.
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Estimate materials before you buy — with visual diagrams.
Loans, interest, tips, discounts and a multi-currency converter.
Track body metrics and daily targets in seconds.
Percentages, ages, unit conversions and fuel costs.
Most popular right now
InstantCalc gives you a growing library of fast, mobile-friendly calculators — no account, no downloads. Each tool runs entirely in your browser, so your numbers stay private and results appear the moment you type.
We started with the calculations people search for most: how much concrete a slab needs, what a mortgage really costs, a BMI reading, or a quick currency conversion across several countries at once. Every calculator includes a plain-English explanation and the formula behind it, so you understand the answer, not just see it.
Yes. Every calculator on InstantCalc is completely free and supported by unobtrusive ads.
No sign-up, no email. Open a tool and start calculating.
Each tool uses standard, documented formulas shown alongside the calculator. For legal, medical or financial decisions, treat results as estimates and consult a professional.