Calculator categories
Choose a subject to see every calculator in it.
Finance
Work out what a loan really costs, how fast savings grow and what inflation does to money over time. Every finance calculator shows its formula and a worked example, so you can check the number yourself.
Mathematics
Everyday arithmetic and statistics, done exactly. Fractions stay as fractions, decimals do not pick up rounding noise, and each tool explains the method behind the answer.
Business, tax & marketing
Pricing, profitability and campaign maths for founders, sellers and marketers. Margin and markup are kept distinct, GST handles both tax-inclusive and tax-exclusive prices, and ROAS shows your break-even point.
Health & fitness
Screening estimates for adults, with the method and its limits stated plainly. These tools are not a diagnosis; a health professional can interpret results in context.
Education
Turn marks and credits into the numbers schools and universities ask for. Grading scales differ between institutions, so each calculator shows exactly which scale it uses.
Date & time
Calendar arithmetic that handles leap years and month lengths correctly, using plain calendar dates so results never shift with your time zone.
Measurement & construction
Conversions based on the exact international definitions of the inch, foot and mile, plus quantity estimates for site work in metric or imperial units.