Unit Converter

Convert between length, weight, temperature, speed, and data units.

0.001

What It Does

Unit Converter handles conversions across five categories: length, weight, temperature, speed, and digital storage. Select a category, enter a value and source unit, and see the converted result instantly. No formulas to remember — all conversions run in your browser.

Supported Units by Category

  • Length — mm, cm, m, km, in, ft, yd, mi, nautical miles
  • Weight / Mass — mg, g, kg, tonnes, oz, lbs, stone
  • Temperature — Celsius, Fahrenheit, Kelvin
  • Speed — m/s, km/h, mph, knots, ft/s
  • Data — bytes, KB, MB, GB, TB, PB (SI and binary)

Quick Reference Conversions

  • 1 inch = 2.54 cm
  • 1 mile = 1.60934 km
  • 1 kg = 2.20462 lbs
  • 1 lb = 0.453592 kg
  • °F to °C: (F − 32) × 5/9
  • 1 GB = 1,073,741,824 bytes (binary) or 1,000,000,000 bytes (SI)

Common Mistakes

Temperature is the most error-prone conversion because it uses an offset formula, not a simple multiplier. Always verify Fahrenheit-to-Celsius results around the 0°C / 32°F boundary. For data units, note whether a tool uses SI (powers of 10) or binary (powers of 2) — the difference is about 7% per gigabyte.

Frequently Asked Questions

How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32: °F = (°C × 9/5) + 32. For a quick estimate, double the Celsius value and add 30 (e.g., 20°C ≈ 70°F). The exact result is 68°F.
What is the difference between kilobytes and kibibytes?
A kilobyte (KB) is 1,000 bytes in SI notation, while a kibibyte (KiB) is 1,024 bytes in binary notation. Operating systems historically used 1 KB = 1,024 bytes, which is why a "500 GB" hard drive shows as less than 500 GB in Windows (which uses binary).
How many kilometers is a mile?
1 mile = 1.60934 kilometers. Equivalently, 1 kilometer = 0.62137 miles. A quick approximation: multiply miles by 1.6 to get km, or multiply km by 0.6 to get miles.
What is 0 Kelvin in Celsius?
0 Kelvin (absolute zero) equals −273.15°C. Kelvin and Celsius share the same scale size — 1 K change equals 1°C change — but Kelvin starts at absolute zero, making it useful in physics and engineering.
How do I convert km/h to m/s?
Divide by 3.6: m/s = km/h ÷ 3.6. For example, 90 km/h = 25 m/s. To convert m/s back to km/h, multiply by 3.6.