About Calculator Uni

Calculator Uni is a free, growing library of calculators for finance, health, math, and everyday life. The goal is simple: give people accurate answers to the numeric questions that come up in real life — a mortgage payment, a body-mass index, a tip split, a retirement projection — without ads that get in the way, sign-up walls, or math you have to take on faith.

Every calculator shows its result instantly as you type, and nearly all of them include a plain-language explanation of the formula, a worked example, and honest notes about the assumptions and limits behind the number. We would rather tell you what a calculator can't account for than pretend it's the final word.

Financial calculators run on precise decimal arithmetic rather than floating-point approximations, so a mortgage schedule reconciles to the cent. Health tools use established, published formulas — the Mifflin-St Jeor equation for metabolic rate, the U.S. Navy method for body fat, the standard amortization and compound-interest formulas for money. Where a formula has known limitations, we say so on the page.

The entire site is statically rendered, which is why pages load almost instantly, and every calculation happens in your browser — the numbers you enter never travel to a server. Tax brackets, contribution limits, and similar figures reflect the 2025 tax year and are updated as the rules change.

We work hard to get the math right, and we test calculators against reference values. That said, every result on Calculator Uni is an estimate for educational purposes — not financial, medical, legal, or tax advice. Real decisions depend on details a calculator can't see, so confirm anything important with a qualified professional and your own official figures.

Found a number that looks wrong, or a calculator you wish existed? Corrections and suggestions genuinely shape what gets built next.

Browse the full A–Z directory, jump into a category — Financial, Health & Fitness, Math, or Everyday — or press ⌘K anywhere to search every tool.