Unit Converters — Length, Weight, Temperature & Volume
66 live calculators · free, instant & privateMeasurement
Length converterMetres, feet, inches and miles with exact factors — eight units at once.Open calculator →Weight converterkg, pounds, stone and ounces — including the stone-and-pounds split.Open calculator →Temperature converterCelsius, Fahrenheit and Kelvin with the formula shown each time.Open calculator →Volume converterLitres, gallons, cups and pints — US and UK measures kept separate.Open calculator →Area converterSquare feet, metres, acres and hectares with exact factors.Open calculator →Speed convertermph, km/h, knots and m/s — road, sea and air in one place.Open calculator →
Cooking
Cooking conversion calculatorCups to grams using each ingredient's real density, plus oven temperatures.Open calculator →Grams to cups converterGrams to cups by ingredient, answered as a real measuring-cup fraction.Open calculator →cups to ml converterUS customary cup 236.588 ml; shows 250 ml metric cupOpen calculator →tablespoons to cups converter16 tbsp/cup, 3 tsp/tbsp, US customaryOpen calculator →oz to cups converter8 fl oz/US cup exact; volume, not weightOpen calculator →
Digital
Data storage converterBytes to GB and GiB — including why your drive looks smaller than advertised.Open calculator →Number Base calculatorBinary, octal, hex, any base 2-36, two's complementOpen calculator →HEX to RGB converterHEX, RGB and HSL with WCAG contrast checkOpen calculator →px to rem converterPixels to rem at any root font sizeOpen calculator →Unix timestamp converterEpoch to date, auto-detects seconds vs millisecondsOpen calculator →Roman numerals converterRoman numerals to numbers, vinculum to 3,999,999Open calculator →
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About these calculators
Most conversions are one multiplication — the hard part is trusting the factor. Every converter here uses the internationally defined value (1 inch is exactly 25.4 mm, 1 pound is exactly 0.45359237 kg) rather than a rounded approximation, and shows the factor it used so you can check the arithmetic yourself.
is the exception: rates move, so that tool fetches a live mid-market rate and stamps it with the time it was pulled. Everything else is pure math running on your device — type a number and the answer is there before you finish, with no round-trip to a server and nothing stored.
More from ListCalc
Every category, same promise: runs in your browser, shows its math, never sees your numbers.