Business & money
- Profit CalculatorYour real margin on eBay, Amazon and Shopify after every fee each one takes.Guide →
- VAT CalculatorAdd or remove VAT at 20%, 5% or a rate you set.Guide →
- Compound Interest CalculatorWhat savings grow to, year by year, with the working shown.Guide →
- Margin & Markup CalculatorTurn cost into price, or price into margin — without the platform fees.Guide →
- Cost of Goods Sold CalculatorThe whole statement — opening stock down to gross profit, line by line.Guide →
- Invoice GeneratorBuild an invoice, proforma or quotation and download it as a PDF.Guide →
Maths
Everyday
- Age CalculatorExact age in years, months and days — or the gap between any two dates.Guide →
- Unit ConverterLength, weight, volume, temperature — and grams to cups, by ingredient.Guide →
- Grams to Cups ConverterHow many cups a weight comes to — for the ingredient you are actually using.Guide →
- Hours CalculatorAdd up worked hours between two times, across days or a whole week.Guide →
Health
Prefer to read how it works?
There are 12 guides — one per calculator — explaining the formula in plain English, with worked examples and an honest note on where each method stops being reliable.
Read the guides