Unit Converter
Numbers & DatesConvert between hundreds of units across length, weight, temperature, volume, area, speed, pressure, energy, power, and data storage with instant results.
3.280839895
Metre (m)1
Kilometre (km)0.001
Centimetre (cm)100
Millimetre (mm)1000
Mile (mi)0.0006213711922
Yard (yd)1.093613298
Foot (ft)3.280839895
Inch (in)39.37007874
Nautical mile0.0005399568035
Light-year1.056971e-16
About Unit Converter
This comprehensive unit converter covers every major physical quantity you're likely to encounter in engineering, science, cooking, logistics, and everyday life. Switch between metric, imperial, and US customary systems with no manual formula lookup required. Simply select a category, enter your value, and all equivalent units update simultaneously. From nanometers to light-years, milligrams to tonnes, and pascals to atmospheres — every conversion is computed with full floating-point precision.
Features
- ✓10+ categories: length, mass, temperature, volume, area, speed, pressure, energy, power, data
- ✓Simultaneous multi-unit output — see all equivalents at once
- ✓Metric, imperial, and US customary systems
- ✓High-precision floating-point calculations
- ✓Searchable unit list within each category
- ✓Keyboard-friendly — tab between fields for rapid entry
- ✓Copy any result to clipboard with one click
- ✓Remembers last-used category and units between sessions
Common Use Cases
- Convert recipe measurements from US cups to metric milliliters
- Calculate shipping weight limits between kilograms and pounds
- Convert screen resolution in pixels-per-inch to pixels-per-centimeter
- Convert vehicle speed between mph and km/h for international travel
- Translate engineering specs between PSI and bar for pressure ratings
- Estimate electricity costs by converting kWh to joules or BTUs
- Convert file sizes between bytes, kilobytes, megabytes, gigabytes, and terabytes
Frequently Asked Questions
QHow accurate are the conversions?
Conversions use IEEE 754 double-precision floating-point arithmetic with exact conversion factors sourced from SI and NIST standards, giving up to 15 significant digits of accuracy.
QDoes the temperature converter handle Kelvin?
Yes. The temperature category supports Celsius, Fahrenheit, Kelvin, and Rankine with correct offset-based formulas (not just scale factors).
QWhat data storage units are supported?
Both SI (KB = 1000 bytes) and IEC binary (KiB = 1024 bytes) prefixes are supported, so you can convert accurately whether you're working with marketing specs or OS file sizes.
QCan I convert between US fluid ounces and imperial fluid ounces?
Yes. The volume category distinguishes between US and imperial fluid ounces, gallons, and pints, as they differ by approximately 20%.
QIs there a way to bookmark a specific conversion?
The URL updates automatically with your selected category, input value, and units, so you can bookmark or share any conversion directly.