09 instruments, 0 sign-ups
Small, exact tools for everyday numbers.
Pick an instrument below. Each one does a single job, shows its work, and gives you a clean readout — no accounts, no ads inside the calculation itself.
01 · Arithmetic
Percentage Calculator
Find a percentage of a number, work out a percent change, or solve for the original value.
02 · Money
Tip Calculator
Split a bill, set a tip percentage, and divide the total evenly across a table.
03 · Units
Length Converter
Convert between metric and imperial length units, from millimetres to miles.
04 · Dates
Age Calculator
Work out exact age, or the time between any two dates, in years, months, and days.
05 · Money
Discount Calculator
Find the sale price and amount saved for any original price and discount percentage.
06 · Health
BMI Calculator
Body Mass Index from height and weight, with the standard reference bands.
07 · Money
Loan Payment Calculator
Estimate the monthly payment and total interest on a loan or mortgage.
08 · Money
Compound Interest Calculator
Project how a lump sum grows over time at a fixed rate and compounding frequency.
09 · Units
Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin, all linked live.