Calculators Tools
Everyday percentage, date and unit maths without a spreadsheet. 3 free tools - every one runs entirely in your browser, nothing you paste in or upload ever leaves your device.
Everyday percentage, date, and unit maths that don't warrant opening a spreadsheet - discount and markup percentages, the number of days or working days between two dates, and metric/imperial conversions across length, weight, temperature, and more.
Percentage Calculator
Work out percentages of a value, percentage change, discounts, tax and what share one number is of another.
Date Calculator
Count days between two dates, add or subtract time, work out age, and count business days.
Unit Converter
Convert between metric and imperial units for length, weight, temperature, area, volume, speed and data.
Choosing the right tool
Percentage Calculator covers discounts, markups, and percentage change. Date Calculator covers durations, deadlines, and age. Unit Converter covers anything measured in physical units. There's no overlap between the three - pick based on what you're calculating, not which name sounds closest.
Common use cases
- Working out a discount or markup percentage for pricing
- Calculating invoice due dates or project deadlines
- Converting shipment weight or dimensions between metric and imperial
Calculators FAQ
Are these calculations exact, or rounded?
Exact, using standard floating-point precision - results are only rounded for display, and each calculator shows enough decimal places to catch a rounding difference that matters, like a financial percentage.