Unit Converter
A recipe from an American site, a road sign in miles, a weather forecast in Fahrenheit. Three different unit systems, one small piece of arithmetic each. Length and weight convert by multiplying by one number. Temperature needs a shift as well as a scale. Pick a category below, choose from and to, type the value, and the result updates at once with the conversion factor shown underneath. Swap the units with one tap to convert back the other way.
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Result
Three Conversions You’ll Use Most
5 miles to kilometres. 1 mile = 1.60934 km, so 5 × 1.60934 = 8.0467 km. That is why a 5-mile run is an 8K race.
70 kg to pounds. 1 kg = 2.20462 lb, so 70 × 2.20462 = 154.3234 = 154.32 lb (rounded to two places).
20 °C to Fahrenheit. °F = 20 × 9/5 + 32 = 36 + 32 = 68 °F. A pleasant spring day in both systems.
The same factors give 0 °C → 32 °F, 100 °C → 212 °F, 6 feet → 1.8288 m, and 10 inches → 25.4 cm.
Why Temperature Plays by Different Rules
Every conversion uses a conversion factor, the number of new units in one old unit. Length and weight convert by multiplication alone. Temperature converts with a formula because its scales start at different zero points.
Length: km = miles × 1.60934 · miles = km ÷ 1.60934 · cm = inches × 2.54 · m = feet × 0.3048
Weight: lb = kg × 2.20462 · kg = lb ÷ 2.20462 · g = oz × 28.3495
Temperature: °F = °C × 9/5 + 32 · °C = (°F − 32) × 5/9 · K = °C + 273.15
Results are rounded to 4 decimal places by default, enough for everyday use without a wall of digits. For rough mental checks, remember: a mile is about 1.6 km, a kilogram is about 2.2 lb, and 20 °C is room temperature (68 °F).
A Note on Kitchen Conversions
Kitchen conversions are approximations. A US cup of flour weighs about 120 g and a cup of sugar about 200 g, but the exact weight depends on how packed the ingredient is and which cup standard the recipe uses. For baking, weighing ingredients beats converting cups.
Good to Know
How many km in a mile?
1.60934 km. Multiply miles by 1.60934: 5 miles = 8.0467 km. For a quick estimate, multiply by 1.6.
How many pounds in a kilogram?
2.20462 lb. Multiply kilograms by 2.20462: 70 kg = 154.32 lb. For a quick estimate, multiply by 2.2.
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32: °F = °C × 9/5 + 32. So 20 °C = 68 °F. To go the other way, subtract 32 and multiply by 5/9.
Are cooking conversions exact?
No. Cups measure volume, grams measure weight, and the link between them depends on the ingredient. A cup of flour is about 120 g, a cup of sugar about 200 g. For baking, a kitchen scale is more reliable than any cup conversion.
How do I convert feet to metres?
Multiply feet by 0.3048: 6 feet = 1.8288 m.
Conversions that go further: the Area Calculator covers square metres and square feet after converting lengths, the Cooking Converter handles cups, grams, and oven temperatures for recipes, the Fuel Cost Calculator uses miles, gallons, and MPG for a trip, and the BMI Calculator takes your height and weight in either unit system. How to Calculate Fuel Cost shows unit conversions in a real trip-cost example. All Math Calculators · All Calculators
Where the numbers come from: conversion factors are the exact international definitions (1 inch = 2.54 cm; 1 lb = 0.45359237 kg; 1 mile = 1.609344 km). Temperature formulas follow the Celsius/Fahrenheit/Kelvin definitions.