Calculators & Converters
Exact conversions and calculations that run in your browser.
Convert
Unit Converter
Length, weight, temperature, volume, area, speed, time and data sizes, using exact definitions.
Time Zone Converter
Convert a date and time between time zones, with daylight-saving gaps and repeats shown.
Calculate
Percentage & Tip Calculator
Percent of, percent change, and tip split between people.
Date Calculator
Days between two dates, or add and subtract days from a date.
Numbers
Numbers and money
Roman Numeral Converter
Convert between numbers from 1 to 3999 and Roman numerals, with strict checking.
Aspect Ratio and Image Size Calculator
Work out a missing width, height or ratio, with the rounding stated.
Compound Interest Calculator
Balance, interest and a yearly table for savings with regular contributions.
Loan and Mortgage Calculator
Monthly payment, total interest and a full repayment schedule.
Health, age, money and pay
BMI Calculator
Body mass index from height and weight, in metric or imperial, with the WHO adult categories.
Age Calculator
Exact age in years, months and days, with total days, weeks and hours lived.
Discount and Markup Calculator
Sale prices, discounts, markup and margin, with the formulas shown.
Salary and Hours Calculator
Hourly, daily, weekly, monthly and annual pay from hours and working days, using the real month lengths.