About TidyCalc

TidyCalc is a free library of 96 online calculators for the money, home and everyday questions people actually search for — from "what's my monthly mortgage payment?" to "how many bags of concrete do I need?" The goal is simple: a clear, correct answer in seconds, with no sign-up, no app to install and no clutter on the page.

What you'll find here

The calculators are grouped into 12 categories spanning finance and business, marketing and SaaS metrics, auto, health and fitness, dates, energy, everyday math, and home-improvement materials like concrete, gravel, soil, flooring, paint and fencing. Each tool runs entirely in your browser — your numbers never leave your device, and there's nothing to download. Most pages also include a short plain-English guide and answers to the questions people ask most, so you understand the result rather than just reading a number.

Who checks these calculators

Figures on this site are compiled and checked by Alex Johnson. We make no claim to trade qualifications, and you should not treat anything here as professional advice — what we can tell you is exactly how each number is produced, so you can check it yourself.

Every calculator page carries a how it works out its numbers panel stating the constants used, their real-world range, and the derivation. Where sources disagree — grout coverage charts differ by two to three times for identical tile — we say so on the page rather than picking one quietly. Worked examples are checked against the calculator on the same page, so the prose and the tool cannot drift apart, and an automated pre-publish check re-verifies the content rules on every build.

If a figure here contradicts the bag, the supplier or your local building code, follow those. They know your specific product and site; we do not.

How we keep the numbers honest

Every result is an estimate for planning. Real-world figures vary with your exact situation, local prices, current rates, taxes and site conditions, so always confirm important numbers with a professional or supplier before you commit money. The finance tools are not financial advice and the health tools are not medical advice — they're starting points to help you think, compare options and ask better questions.

How the site stays free

Some links on this site are affiliate links: if you buy through them we may earn a small commission at no extra cost to you, and we may show ads alongside the calculators. That's what keeps every tool here free to use, with no paywall and no account required. We only suggest products that genuinely relate to the calculator you're using.