Convert anything, instantly
Accurate converters for measurements, cooking, cars, computers and time — exact factors, no ads in the way of the answer.
⭐ Featured tools
🆕 New tools
📚 Guides
📏 Measurement
Length Converter
Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards, miles and nautical miles with exact factors.
Weight Converter
Convert pounds, kilograms, ounces, grams, stone and tons with exact factors.
Temperature Converter
Convert temperatures between Celsius, Fahrenheit and Kelvin instantly, with the formulas shown.
Volume Converter
Convert liters, milliliters, US and UK gallons, quarts, pints, cups, fluid ounces and cubic feet.
Area Converter
Convert square feet, square meters, acres, hectares, square miles and more with exact factors.
Speed Converter
Convert miles per hour, kilometers per hour, meters per second, knots and feet per second.
💾 Digital & Numbers
Data Storage Converter
Convert bits, bytes, KB, MB, GB, TB and binary KiB, MiB, GiB, TiB units.
Number Base Converter
Convert whole numbers between binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16).
Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals to numbers, from 1 to 3,999.
Frequently Asked Questions
Do I need to sign up or log in?
No. Every calculator works instantly without an account. A free account is only needed if you want to save results (up to 30) and see them later.
Is my data stored anywhere?
The numbers and dates you type are calculated in your browser and are not sent to us. We keep basic visit statistics (page visited, IP address, browser, time) and, if you save a result, that saved result in your account. The AI Assistant sends your question to an AI provider to answer it.
Are the results exact?
Date and age maths is exact. Money, tax and health tools are estimates based on published formulas and official tables, and are not professional advice.