Unit Converters
Convert between metric, US customary and imperial units with factors checked against NIST and the SI Brochure. Every converter shows the exact formula it uses, so you can see where the answer comes from.
Where countries use the same name for different units, such as US and UK gallons, the metric and short ton, or kilobytes and kibibytes, each variant is listed separately and clearly labelled.
Everyday measurements
- Length Converter Convert cm, inches, feet, meters, miles and more, exactly.
- Weight Converter Convert kg, pounds, ounces, grams and stone, exactly.
- Temperature Converter Convert Celsius, Fahrenheit, Kelvin and Rankine, with the formula.
- Height Converter Convert cm or meters to feet and inches, and back.
- Volume Converter Convert liters, gallons, cups and fluid ounces, US and UK.
- Cooking Converter Cups, spoons and mL to grams for flour, sugar, butter and more.
- Speed Converter Convert mph, km/h, m/s, knots and ft/s instantly.
- Area Converter Convert square feet, square meters, acres, hectares and marla.
- Time Unit Converter Convert seconds, minutes, hours, days, weeks, months and years.
- Shoe Size Converter Convert adult shoe sizes between US, UK and EU, or foot length.
Science and engineering
- Pressure Converter Convert psi, bar, kPa, atm, mmHg and inHg.
- Fuel Economy Converter Convert US mpg, UK mpg, L/100 km and km/L.
- Energy Converter Convert joules, calories, kWh, BTU and therms.
- Power Converter (W, kW, HP) Convert watts, kilowatts, horsepower, PS and BTU/h.
- Angle Converter Convert degrees, radians, gradians, mils and DMS.
- Torque Converter Convert newton meters, pound-feet, inch-pounds and kgf·m exactly.
- Force Converter Convert newtons, pounds-force, kilograms-force, kips and dynes exactly.
- Density Calculator Find density, mass or volume from the other two.
- Frequency Converter Convert hertz, kHz, MHz, GHz and rpm, exactly.
Computing and numbers
- Data Storage Converter Convert bytes, KB, MB, GB and TB, decimal or binary.
- Number Base Converter Convert whole numbers between binary, decimal, hex, octal and any base.
- Roman Numeral Converter Convert numbers to Roman numerals and back, with the working.
- Number to Words Converter Spell out any number in English words, or write a cheque amount.
- Data Transfer Rate Converter Convert Mbps to MB/s, Gbps, KiB/s and other data speeds.
Popular conversions
- cm to inches
- inches to cm
- meters to feet
- feet to meters
- km to miles
- miles to km
- mm to inches
- inches to mm
- inches to feet
- feet to inches
- kg to lbs
- lbs to kg
- grams to ounces
- ounces to grams
- pounds to ounces
- ounces to pounds
- kg to stone
- stone to kg
- celsius to fahrenheit
- fahrenheit to celsius
- celsius to kelvin
- fahrenheit to kelvin
- kelvin to celsius
- kelvin to fahrenheit
- gallons to liters
- liters to gallons
- cups to ml
- ml to oz
- oz to ml
- tablespoons to cups
- sq ft to sq m
- sq m to sq ft
- acres to sq ft
- sq ft to acres
- mph to km/h
- km/h to mph
- knots to mph
- mph to knots
- psi to bar
- bar to psi
- psi to kPa
- kPa to psi
- kcal to cal
- hp to kW
- kW to hp
- watts to hp
- hp to watts
- MB to GB
- GB to MB
- GB to TB
- TB to GB
- mpg to L/100 km
- L/100 km to mpg
- degrees to radians
- radians to degrees
- minutes to hours
- hours to minutes
- All unit conversions