Free Online Unit Converter
Convert length, weight, temperature, volume, area, speed, and digital storage units instantly.
Length Converter
Convert units of length like meters, kilometers, miles, and feet.
Weight Converter
Convert units of weight like kilograms, grams, pounds, and ounces.
Temperature Converter
Convert temperature units like Celsius, Fahrenheit, and Kelvin.
Speed Converter
Convert speed units like m/s, km/h, mph, and knots.
Volume Converter
Convert volume units like liters, milliliters, gallons, and pints.
Area Converter
Convert area units like square meters, hectares, and square feet.
Digital Storage Converter
Convert digital storage units like bytes, kilobytes, and gigabytes.
Time Converter
Convert durations from nanoseconds to decades.
Pressure Converter
Convert pressure units used in science, weather, engineering, and tires.
Energy Converter
Convert energy used in electricity, heating, nutrition, and physics.
Power Converter
Convert rates of energy use for electrical and mechanical systems.
Force Converter
Convert force units used in mechanics, structures, and testing.
Angle Converter
Convert plane angles for geometry, navigation, and engineering.
Data Rate Converter
Convert network and file-transfer speeds in bits or bytes per second.
Cooking Converter
Convert recipe volume measures. Weight conversions require an ingredient-specific density.
Fuel Economy Converter
Convert fuel economy while accounting for reciprocal consumption units.
Frequency Converter
Convert frequencies from microhertz to terahertz and rotational rates.
Frequently asked questions
How many kilometers are in a mile?
One mile equals 1.609344 kilometers exactly. For this and any other specific conversion, use the miles-to-kilometers page, which shows the formula, the factor, and a quick calculator.
Is OmniUnit free?
Yes. OmniUnit is free to use with no account and no sign-up.
Do my conversions get uploaded anywhere?
No. Every conversion is computed locally in your browser. Your conversion values are never uploaded to a server.
How many units does OmniUnit support?
OmniUnit supports 150+ units across 17 measurement categories, from everyday length, weight, and volume to technical and scientific units.
Do I need to install anything to use OmniUnit?
Nothing to install. OmniUnit is a web app — open it in any modern browser on desktop, phone, or tablet and convert immediately.
How do I convert between two specific units?
Pick the two units you need — for example kilograms to pounds. Each pair page shows the exact conversion formula, the factor, and a calculator pre-set to that pair.
How accurate are the conversions?
Conversion factors are exact published definitions, so results are as precise as the numbers you enter. For critical engineering or trade use, always double-check against an authoritative reference.