Unit Converter — Convert Any Measurement Instantly
Our free unit converter handles 15 categories of measurements with hundreds of units — from everyday conversions like feet to meters and Celsius to Fahrenheit, to specialized units like parsecs, pascals, and petabytes. Enter any value, select your units, and see instant conversions across the entire unit category at once.
Common Unit Conversions Reference
Length Conversions
| From | To | Multiply By |
|---|
| 1 inch | centimeters | 2.54 |
| 1 foot | meters | 0.3048 |
| 1 yard | meters | 0.9144 |
| 1 mile | kilometers | 1.60934 |
| 1 kilometer | miles | 0.621371 |
| 1 meter | feet | 3.28084 |
| 1 cm | inches | 0.393701 |
| 1 nautical mile | km | 1.852 |
Weight Conversions
| From | To | Multiply By |
|---|
| 1 kilogram | pounds | 2.20462 |
| 1 pound | kilograms | 0.453592 |
| 1 ounce | grams | 28.3495 |
| 1 gram | ounces | 0.035274 |
| 1 stone | kilograms | 6.35029 |
| 1 short ton | kilograms | 907.185 |
| 1 metric ton | pounds | 2,204.62 |
Temperature Conversions
| Conversion | Formula | Example |
|---|
| °C to °F | (°C × 9/5) + 32 | 100°C = 212°F |
| °F to °C | (°F - 32) × 5/9 | 32°F = 0°C |
| °C to K | °C + 273.15 | 0°C = 273.15K |
| K to °C | K - 273.15 | 373.15K = 100°C |
Volume Conversions
| From | To | Multiply By |
|---|
| 1 US gallon | liters | 3.78541 |
| 1 liter | US gallons | 0.264172 |
| 1 Imperial gal | liters | 4.54609 |
| 1 US cup | milliliters | 236.588 |
| 1 tablespoon | milliliters | 14.7868 |
| 1 teaspoon | milliliters | 4.92892 |
| 1 fluid ounce | milliliters | 29.5735 |
| 1 cubic foot | liters | 28.3168 |
Metric System Prefixes
The metric system uses standardized prefixes to represent multiples and fractions of base units. Understanding these prefixes unlocks all metric conversions:
| Prefix | Symbol | Factor | Example |
|---|
| Tera | T | 10¹² | 1 TB = 10¹² bytes |
| Giga | G | 10⁹ | 1 GHz = 10⁹ Hz |
| Mega | M | 10⁶ | 1 MW = 10⁶ watts |
| Kilo | k | 10³ | 1 km = 1,000 m |
| Hecto | h | 10² | 1 hm = 100 m |
| Deca | da | 10¹ | 1 dam = 10 m |
| Base | — | 10⁰ | meter, gram, liter |
| Deci | d | 10⁻¹ | 1 dm = 0.1 m |
| Centi | c | 10⁻² | 1 cm = 0.01 m |
| Milli | m | 10⁻³ | 1 mm = 0.001 m |
| Micro | μ | 10⁻⁶ | 1 μm = 10⁻⁶ m |
| Nano | n | 10⁻⁹ | 1 nm = 10⁻⁹ m |
| Pico | p | 10⁻¹² | 1 pm = 10⁻¹² m |
US vs Imperial (UK) Units — Key Differences
The United States and the United Kingdom both use "imperial" units but they are NOT identical. Several units have different values:
| Unit | US Value | UK (Imperial) Value | Difference |
|---|
| Fluid Ounce | 29.574 mL | 28.413 mL | US is 4% larger |
| Cup | 236.6 mL | 284.1 mL | UK is 20% larger |
| Pint | 473.2 mL | 568.3 mL | UK is 20% larger |
| Quart | 946.4 mL | 1,136.5 mL | UK is 20% larger |
| Gallon | 3,785.4 mL | 4,546.1 mL | UK is 20% larger |
| Ton (weight) | 907 kg | 1,016 kg | UK ton is larger |
Digital Storage: SI vs Binary
Digital storage has two competing conventions that use the same prefix names for different values:
| Unit | SI (Decimal) | Binary | IEC Name | Difference |
|---|
| Kilobyte (KB) | 1,000 bytes | 1,024 bytes | KiB | 2.4% |
| Megabyte (MB) | 1,000,000 B | 1,048,576 B | MiB | 4.9% |
| Gigabyte (GB) | 10⁹ bytes | 2³⁰ bytes | GiB | 7.4% |
| Terabyte (TB) | 10¹² bytes | 2⁴⁰ bytes | TiB | 10% |
| Petabyte (PB) | 10¹⁵ bytes | 2⁵⁰ bytes | PiB | 12.6% |
Speed Conversions
| From | mph | km/h | m/s | knots |
|---|
| 1 mph | 1 | 1.609 | 0.447 | 0.869 |
| 1 km/h | 0.621 | 1 | 0.278 | 0.540 |
| 1 m/s | 2.237 | 3.600 | 1 | 1.944 |
| 1 knot | 1.151 | 1.852 | 0.514 | 1 |
| Mach 1 | 767 | 1,235 | 343 | 667 |