About Everyday Calculators

What this site is

Everyday Calculators is a free collection of seventeen small, fast tools for the calculations that come up in ordinary life — tips, percentages, discounts, VAT, splitting a bill, converting units, area, loans, a mortgage, savings and compound interest, paying off debt, profit margin, fuel cost, salary, BMI and calories, dates and time. Alongside the tools we publish plain-English guides that explain how each calculation works, several with reference tables you can use on their own. Every tool answers a single question quickly, with no clutter and no sign-up.

Who is behind the site

Everyday Calculators is an independent project, built and maintained by hand by its owner, Daniel. It is not an auto-generated content farm: every calculator is coded deliberately, each formula is chosen and checked against its source, and every explanation is written to be genuinely useful rather than to fill space. If something looks wrong, a real person reads the message and fixes it — you can write to the owner directly at everydaycalculatorssupp@gmail.com.

How we build and test our calculators

Each calculator is built around a documented, standard formula rather than a black box. Before a tool goes live we test it two ways: we check the maths against worked examples by hand, and we run automated checks that load every page, confirm there are no script errors, and verify the results for known inputs. For each calculator we also write a plain-English explanation of how the calculation works, a worked example, and a short FAQ, so you can see the method — not just the answer.

The formulas and sources we use

We use well-established formulas and are transparent about the standards behind them. Loans and mortgages use the standard amortization formula; savings use month-by-month compounding; BMI is weight in kilograms divided by height in metres squared, with the weight categories from the World Health Organization; daily calories use the Mifflin-St Jeor equation for resting metabolism; VAT and discounts are simple percentage arithmetic; and unit and area conversions use the exact factors defined in the International System of Units (SI, NIST). Reference data is dated and attributed — for example, our table of standard VAT rates cites the Tax Foundation and the date it applies. Where a figure depends on your country or provider — a tax rate, a lender's APR — we say so and point you to the authoritative source rather than guessing.

Your data stays in your browser

Every calculator runs entirely in your browser. There is nothing to install, no account to create, and no numbers are sent to a server — your inputs are processed on your own device and the result appears as you type. That also means the site keeps working offline once loaded, and your figures stay private to you.

A note on accuracy

The calculators are careful, but they are still quick estimates and they assume the simple case (a fixed rate, a rectangular room, and so on). For financial decisions (loans, mortgages, taxes) and health decisions (BMI, calories), treat the results as a starting point and confirm important figures with a qualified professional or your provider's exact numbers.

Five languages

The site is available in English, German, Dutch, French and Russian, with the currency and number formatting adjusted to each. You can switch language at any time from the selector in the header, and it remembers your choice.

Get in touch

Found a bug, have an idea for a new calculator, or spotted something that looks wrong? We would genuinely like to hear it — visit the contact page or email us at everydaycalculatorssupp@gmail.com.