All In One Converter Tool
A free unit converter for weight, length, temperature, volume, area, speed, time and data, plus currency, color codes and 16 converter categories in all. Exact factors, no signup.
Common conversions, worked out
Computed with the same exact factors as the converter above.
| Convert | Answer | Rule |
|---|---|---|
| 150 lb to kg | 68.03886 kg | × 0.45359237 (exact) |
| 10 in to cm | 25.4 cm | × 2.54 (exact) |
| 6 ft to m | 1.8288 m | × 0.3048 (exact) |
| 5 km to mi | 3.106856 mi | ÷ 1.609344 |
| 100 °F to °C | 37.77778 °C | (°F − 32) × 5/9 |
| 1 gal to L | 3.785412 L | × 3.785411784 (exact) |
| 1,000 ft² to m² | 92.90304 m² | × 0.09290304 (exact) |
| 60 mph to km/h | 96.56064 km/h | × 1.609344 |
| 1 GB to MB | 1,000 MB | × 1,000 (SI) or 1,024 MiB per GiB |
Factors: NIST SP 811, Appendix B.8; inch defined as exactly 25.4 mm (NIST Office of Weights and Measures).
Quick access
Everyday converters
Measurement basics — length, weight, temperature, and more.
Popular conversions
Each with the exact formula, a chart and worked examples.
- Inches to Feet
- Centimeters to Feet
- Ounces to Cups
- Square Feet to Acres
- Quarts to Cups
- Feet to Inches
- Knots to Miles per Hour
- Kelvin to Celsius
- Megabytes to Gigabytes
- Kilobytes to Megabytes
- Hectares to Acres
- Celsius to Kelvin
- Pints to Cups
- Feet to Yards
- Meters to Yards
- Seconds to Hours
- Meters per Second to Miles per Hour
- Gigabytes to Terabytes
- Gigabytes to Megabytes
- Pounds to Ounces
- Ounces to Pounds
- Centimeters to Inches
- Inches to Centimeters
- Kilograms to Pounds
- Pounds to Kilograms
- Fahrenheit to Celsius
- Celsius to Fahrenheit
- Feet to Meters
- Meters to Feet
- Kilometers to Miles
- Miles to Kilometers
- Millimeters to Inches
- Inches to Millimeters
- Cubic Feet to Gallons
- Milliliters to Fluid Ounces
- Gallons to Liters
- Liters to Gallons
- Ounces to Grams
Converter tools
Time to Decimal Hours
7:45 → 7.75 hours, and back
Fraction ↔ Decimal ↔ Percent
3/8 = 0.375 = 37.5%, nearest 1/16
Fuel Economy Converter
mpg (US/UK) ↔ L/100 km ↔ km/L
Roman Numeral Converter
1994 ↔ MCMXCIV
Time Zone Converter
Your time in New York, London, Tokyo…
Shoe Size Converter
US men's & women's ↔ UK ↔ EU ↔ JP ↔ foot length
Torque Converter
N·m ↔ lb·ft ↔ lb·in ↔ kgf·m, plus horsepower at rpm
Watts to Amps Converter
W → A at any voltage, DC, single- or three-phase
Military Time Converter
1430 ↔ 2:30 PM, with a 24-hour chart
Scientific Notation Converter
123000 ↔ 1.23 × 10⁵, E notation, engineering + SI prefix
Number to Words Converter
1,234.56 → words, cheque wording, dollars & cents
Tech & specialty converters
For developers, designers, scientists and curious minds.
How these converters work
Every unit converter here goes through one base unit. Length runs through the metre, weight through the kilogram, volume through the litre and energy through the joule, so any unit converts to any other in a single step and the result never drifts the way a chain of rounded conversions can. The factors are the exact legal definitions where one exists: an inch is 25.4 mm, a pound is 0.45359237 kg and a US gallon is 3.785411784 litres.
Temperature is the exception, because Celsius, Fahrenheit, Kelvin and Rankine have different zero points as well as different step sizes. Those conversions use the full formula, such as °F = °C × 9/5 + 32, rather than a single factor.
Each conversion page shows the formula, a chart of common values and worked examples, so you can check the answer by hand. The arithmetic runs in your browser, so nothing you type is uploaded.
Frequently asked questions
What is a unit to unit converter?
A tool that turns a measurement in one unit into the same quantity in another, such as pounds to kilograms or inches to centimeters. The converter at the top of this page handles weight, length, temperature, volume, area, speed, time and data in one box; pick a category, type a number and choose the two units.
How do I convert lbs to kg?
Multiply pounds by 0.45359237, the exact legal definition of the pound. For example, 150 lb × 0.45359237 = 68.03886 kg. To go the other way, divide kilograms by 0.45359237 (or multiply by about 2.20462).
Is there a conversion chart for lbs to kg?
Yes. The pounds to kilograms page has a chart from 1 lb upward with every value worked out from the exact factor, plus body-weight and luggage examples you can print.
How do I convert weight units?
Choose Weight in the converter, type the amount and pick the units: milligrams, grams, kilograms, ounces, pounds, stone and US or imperial tons are all there. Every unit goes through the kilogram, so any pair converts in one exact step.
How accurate are these conversions?
Each factor is the exact definition published by NIST where one exists (1 inch = 25.4 mm, 1 pound = 0.45359237 kg, 1 US gallon = 3.785411784 L), and results show up to 7 significant figures. Temperature uses the full offset formula rather than a single factor.