Free unit converters — length, weight, temperature, volume, speed
Straight unit conversions without the ad maze: length and distance, weight and mass, temperature, volume, speed, area, pressure and data size. Type a value, pick the units, get an exact result you can trust — handy for recipes, travel, shipping, lab work or homework where one wrong factor changes everything.
Length Converter (mm, cm, m, km, in, ft, yd, mi)
Convert between metric and imperial length units instantly. Includes mm, cm, m, km, inches, feet, yards, and miles.
Temperature Converter (Celsius, Fahrenheit, Kelvin, Rankine)
Convert between Celsius, Fahrenheit, Kelvin, and Rankine. All four scales update at once.
Weight Converter (kg, g, t, lb, oz, stone, mg)
Convert between metric and imperial mass units. Includes mg, grams, kilograms, tonnes, ounces, pounds, and stones.
Area Converter (m², ft², acre, hectare, tsubo)
Convert between metric, imperial, and Japanese area units. Includes m², km², hectare, ft², acre, mile², and tsubo.
Time Unit Converter (ms, s, min, h, days, weeks, months, years)
Convert between time units from milliseconds to years. Months use the average length, years use the Julian definition.
Data Size Converter (B, KB, MB, GB, TB — SI and IEC)
Convert digital storage sizes between bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes. Switch between SI (1000) and IEC binary (1024).
Volume Converter (mL, L, gal, fl oz, cup, tsp)
Convert between metric and US/UK volume units. Includes mL, liters, m³, teaspoons, tablespoons, fluid ounces, cups, pints, quarts, and gallons.
Speed Converter (km/h, mph, m/s, knot, Mach)
Convert between common speed units: km/h, mph, m/s, ft/s, knots, and Mach. Used for vehicles, weather, aviation, and physics.
Fuel Economy Converter (mpg US/UK, km/L, L/100km)
Convert vehicle fuel economy between mpg (US), mpg (UK), km per liter, and L per 100 km. Distinguishes US and UK gallons.
Pressure Converter (Pa, bar, psi, atm, mmHg)
Convert between pressure units: Pascal, bar, psi, atmosphere, mmHg, Torr, and more. All units update simultaneously when you change one.
Angle Converter (degrees, radians, gradians, turns)
Convert angles between degrees, radians, gradians, turns, arcminutes, and arcseconds. All 6 units update simultaneously.
Power Unit Converter (W, kW, hp, BTU/h)
Convert between power units: watts, kilowatts, megawatts, mechanical horsepower, metric horsepower (PS), BTU/hour, foot-pounds/second, cal/s, kcal/h.
Cooking Unit Converter — Cups, Tbsp, Tsp, ml, g, oz
Convert cooking measurements between cups, tablespoons, teaspoons, fluid oz, ml, and liters. Includes ingredient-aware weight converter for flour, sugar, butter, and more.
CSS Unit Converter — px, rem, em, pt, % Online
Convert CSS units instantly: px to rem, rem to px, em, pt, and %. Set your base font size for accurate rem and em conversions. Essential for responsive web design.
Currency Converter — 31 Currencies, Instant Results
Convert between 31 major world currencies with static 2025 reference rates. Instant results, no sign-up, works offline.
Wind Chill Calculator — Feels Like Temperature
Calculate the wind chill index and see how cold it feels with current temperature and wind speed.
Heat Index Calculator — Feels Like Temperature & Humidity
Calculate the apparent 'feels like' temperature from air temperature and relative humidity using the NWS Rothfusz formula.
Coffee Ratio Calculator – Water to Coffee
Find the perfect water-to-coffee ratio for pour-over and drip.