About TidyCalcs

TidyCalcs is a small collection of free online calculators built around one idea: when you need a quick answer to an everyday math question, you shouldn't have to fight through clutter to get it.

Why we built this

Most of life's recurring math questions are simple in shape but tedious to do by hand. What will this mortgage actually cost me each month? How many euros will my dollars buy? How many calories does my body need? How many days until the wedding? The web has plenty of tools that answer these questions — but many of them are slow to load, demand sign-ups, or bury the result under walls of clutter.

TidyCalcs takes the opposite approach. Each tool does one job, loads fast, works entirely in your browser, and gives you the answer immediately. No accounts. No downloads. No noise.

Our tools

• Mortgage Calculator — monthly payment, total interest, and a full year-by-year amortization schedule, including property tax and insurance.
• Currency Converter — conversions across 150+ world currencies using mid-market exchange rates updated daily.
• Calorie Calculator — daily calorie needs estimated from your age, height, weight, and activity level.
• BMI Calculator — body mass index in metric or imperial units, with healthy-range context.
• Age Calculator — exact age in years, months, and days, for any birth date and any reference date.
• Date Calculator — the number of days between any two dates, or a new date from adding or subtracting time.

How our calculators work

We use standard, published methods rather than black boxes. The mortgage calculator applies the conventional fixed-rate amortization formula used by lenders. The currency converter is based on mid-market rates — the midpoint between buy and sell prices that you see quoted on financial news sites. The calorie calculator estimates your basal metabolic rate with the Mifflin-St Jeor equation, then scales it by your activity level. Where a calculation involves judgment or assumptions, we say so on the tool's page.

What our results are (and aren't)

Our calculators are designed to be accurate, but they provide general information, not professional advice. A mortgage estimate is not a loan offer; your lender's quote will reflect your credit, fees, and local taxes. Exchange rates shown are mid-market reference rates; banks and transfer services apply their own margins. Calorie and BMI figures are population-level estimates that can't account for your individual health picture. For decisions that matter, please consult a qualified professional — a licensed lender or financial advisor, or your doctor.

How this site is supported

TidyCalcs is free to use and is supported by advertising. Ads keep the tools free without requiring accounts or subscriptions. You can read more about how advertising works on this site in our Privacy Policy.

Get in touch

Spotted a bug, have a question, or want to suggest a new calculator? We'd genuinely like to hear it — visit the contact page and send us a note.