About Life Calculator

A free reference site for everyday calculations — and how it is built.

Life Calculator is a free reference site. It exists to answer a narrow class of question well: the everyday calculations people look up, done accurately, explained clearly, and without requiring an account or an app.

What is here

66 calculators across six areas — health and fitness, personal finance, mathematics, dates and time, unit conversion, and practical household problems. Every tool is free, works on a phone, and needs no sign-up.

What makes these different

A calculator that only produces a number asks you to trust it. We would rather you did not have to. Each page therefore includes:

• The formula, written out. Not hidden in the JavaScript — printed on the page in a form you can follow.
• A worked example. Real numbers, each step shown, so you can confirm that our implementation does what the formula says.
• The assumptions and limits. Where the model breaks down, who it does not apply to, and why another site may legitimately give a different answer.

This is also why we publish roughly a hundred calculators rather than thousands. Each one is written and checked individually. We would rather have a page you can rely on than a page that merely exists.

Privacy by architecture

Every calculation runs in JavaScript in your own browser. No calculator form on this site submits data anywhere. Your weight, your salary, your loan balance and your dates are never transmitted to us, never logged and never stored, because the architecture gives us no way to receive them. Open your browser's network inspector while you use any tool and you will see that nothing leaves the page.

How we check the maths

Every formula is implemented from a primary source — the original published paper, a standards body definition, or official documentation — and then tested against worked examples with known answers. A tool that disagrees with its reference case does not get published. Pages carry a “last reviewed” date, and we revisit them when the underlying rules change.

We still make mistakes. If you find one, tell us at hello@lifecalculator.space and we will fix it and say so on the page. Our editorial policy sets out the full process.

How the site is paid for

Advertising, served by Google AdSense. We do not sell data, we do not run affiliate links, and advertisers have no influence over what we publish or what a calculator returns. If that ever changes, it will be disclosed on the page concerned. Ads are kept out of the reading flow and are never disguised as content.

What this site is not

It is a reference, not an adviser. The health tools use population averages and cannot diagnose anything. The finance tools ignore your provider's fees, your tax position and your contract terms. For decisions that matter, use these numbers to prepare your questions, then put them to a professional who can see your full situation. Our disclaimer spells this out.

Get in touch

Corrections, suggestions for a calculator we are missing, or anything else: hello@lifecalculator.space, or the contact form. Every message is read.

Last updated: September 22, 2026.