30 free tools · Converters
Free Unit Converters
Convert between metric, imperial and US units in one step. Pick the units, type a number, and the result updates instantly, together with a reference table of common values.
Use them as often as you like — free, with no sign-up and no daily limits.
- Free
- No sign-up
- Phone & computer
- Measurement units20
- Numbers & numerals5
- Sizes, screens & print5
30 tools
All Unit Converters
Grouped by what they help you do.
30 tools
- Unit ConverterPopularConvert any common unit: length, weight, temperature, volume and more.
- Length ConverterPopularMeters, feet, inches, centimeters, miles, kilometers and more.
- Weight ConverterPopularKilograms, pounds, ounces, grams, stones and tons.
- Temperature ConverterPopularCelsius, Fahrenheit and Kelvin, with the formulas shown.
- Area ConverterSquare meters, square feet, acres, hectares and more.
- Volume ConverterLiters, gallons (US and UK), cups, milliliters and cubic units.
- Speed Converterkm/h, mph, meters per second, knots and feet per second.
- Data Size ConverterBytes, KB, MB, GB and TB — in both decimal and binary units.
- Pressure ConverterPSI, bar, pascals, atmospheres and mmHg.
- Energy ConverterJoules, calories, kilocalories, kWh and BTU.
- Time ConverterConvert between seconds, minutes, hours, days, weeks, months and years.
- Power ConverterWatts, kilowatts, horsepower, BTU/h and tons of refrigeration.
- Frequency ConverterHz, kHz, MHz, GHz, RPM and radians per second.
- Force ConverterNewtons, kilonewtons, pounds-force, kilograms-force and dynes.
- Torque ConverterNewton-metres, pound-feet, pound-inches and kgf·m.
- Density Converterkg/m³, g/cm³, g/mL, lb/ft³ and pounds per gallon.
- Angle ConverterDegrees, radians, gradians, arcminutes, arcseconds and turns.
- Fuel Economy ConverterMPG (US and UK), km/L and L/100 km — converted correctly both ways.
- Data Transfer Rate ConverterPopularConvert Mbps, MB/s, Gbps and MiB/s, and see how long a download really takes after overhead.
- Cooking Unit ConverterPopularCups, tablespoons, millilitres, grams and ounces — with ingredient densities.
- Roman Numeral ConverterConvert numbers to Roman numerals and back, from 1 to 3,999.
- Number to Words ConverterWrite any number out in English words, including cheque format.
- Decimal to Fraction ConverterTurn any decimal — including repeating decimals — into a simplified fraction.
- Scientific Notation ConverterWrite numbers in scientific, E and engineering notation, with significant figures.
- Number FormatterFormat numbers with thousands separators for any country, round, or make them compact.
- Pixels to Print Size ConverterHow big an image prints at any DPI — or the pixels you need for a print size.
- Screen Size CalculatorWidth, height and pixel density of any screen from its diagonal and aspect ratio.
- Clothing Size ConverterUS, UK, EU, Italian and Japanese clothing sizes for women and men.
- Shoe Size ConverterUS, UK and EU shoe sizes and foot length for men and women.
- Paper Size ChartExact A, B, C and US paper sizes in mm, inches, points and pixels.
Before you start
Good to know
US vs UK (imperial) units
Some units share a name but not a size. A US gallon is about 3.785 litres while a UK (imperial) gallon is about 4.546 litres. A US fluid ounce is slightly larger than a UK fluid ounce. The converters label these separately so you always pick the right one.
Converters guides
Step-by-step help that goes with these tools.
Converters
Common questions
Quick answers about these free tools.
How precise are the conversions?
Results are calculated to full precision and rounded only for display. You can copy the full-precision result.
Can I convert temperatures?
Yes. The temperature converter handles Celsius, Fahrenheit, Kelvin and Rankine, which need formulas rather than a single multiplication factor.
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