About
About CalcVault
A small, fast set of free calculators for the numbers that come up day to day — splitting a bill, working out a mortgage payment, checking your BMI, or solving a bit of math.
What it is
CalcVault is a collection of free online calculators covering everyday tools, finance, health and fitness, and math. Every calculator runs entirely in your browser: there's no account to create, nothing to install, and the numbers you enter never leave your device.
How it's built
The whole site is plain HTML, CSS, and JavaScript with no tracking beyond simple, anonymous traffic measurement. That keeps pages quick to load on any phone and keeps your inputs private. Formulas follow widely used standards, and each tool is tested against known values.
How we keep the numbers accurate
Accuracy is the whole point of a calculator, so each tool is built around the same formula a textbook or lender would use, not an approximation. Mortgage and loan payments use the standard amortization formula; BMI follows the WHO height-and-weight definition and category bands; BMR and calorie figures use the Mifflin–St Jeor equation. Before a calculator goes live, we check its output against worked examples with known answers, and we re-test whenever the code changes. Each calculator page shows the exact formula and a worked example so you can verify the result yourself rather than take it on trust.
That said, these tools are for general information and education. For a mortgage decision, a medical question, or anything with real consequences, treat the result as a starting point and confirm it with a qualified professional. If you ever get a result that looks wrong, please tell us — corrections are a priority.
How it stays free
The site is supported by advertising. That lets the calculators stay free for everyone, with no paywalls or sign-ups. We don't sell the numbers you enter, and calculations happen on your device, not on a server. See our privacy policy for how ads and analytics use cookies.
Who's behind it
CalcVault is an independent project built and maintained by the CalcVault team — a small group that has been building and refining these calculators since 2025. We use the same tools ourselves for everyday math, splitting bills, and working through finance and health questions, which is how rough edges and wrong results get caught. Spotted a bug, a wrong result, or have a calculator you'd like to see? We'd genuinely like to hear it — reach out via the contact page.
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