Instantly convert between units of measurement, currency, temperature, and more.
Convert between inches, feet, yards, meters, kilometers, miles, and more. Imperial and metric.
Convert between pounds, kilograms, ounces, grams, stone, and tons instantly.
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Convert between gallons, liters, fluid ounces, cups, quarts, pints, and more.
Convert between Fahrenheit, Celsius, Kelvin, and Rankine instantly.
Unit conversion is one of those tasks that feels trivial until it costs you something. A recipe calls for 250 grams of flour and your kitchen scale reads in ounces. A European supplier quotes a part in millimetres and your drawings are in inches. A hotel abroad lists the room at 28 square metres and you have no sense of whether that is generous or cramped. Our 11 free converters handle length, weight, area, volume, temperature, cooking measurements, currency, clothing sizes, and shoe sizes, with no sign up and no app to install.
Every converter runs instantly in your browser and works both directions. The currency converter pulls live exchange rates rather than stale hardcoded values, so a figure you calculate today reflects today's market. The cooking converter accounts for ingredient density, which matters more than most people realise: a cup of flour and a cup of sugar differ by roughly 75 grams, and that gap is enough to ruin a loaf of bread.
| What You Are Doing | Best Converter | Common Units |
|---|---|---|
| Following a recipe from another country | Cooking Measurement Converter | Cups, grams, millilitres |
| Packing for international travel | Weight Converter, Length Converter | Pounds, kilograms, inches |
| Buying clothes or shoes from an overseas site | Clothing Size Converter, Shoe Size Converter | US, UK, EU sizing |
| Estimating materials for a home project | Area Converter, Volume Converter | Square feet, cubic yards |
| Reading a weather forecast abroad | Temperature Converter | Fahrenheit, Celsius |
| Budgeting a trip or paying an overseas invoice | Currency Converter | Live exchange rates |
Most of the world settled on metric decades ago, but imperial units persist in American construction, cooking, and consumer products, and in British road signs and pub measures. The result is that a single project can span both systems without warning. Lumber is sold in nominal inches while insulation is rated in metric R values. A running app reports kilometres while a treadmill shows miles. Screen sizes are in inches everywhere on earth, including in countries that use metric for everything else.
The practical takeaway is not that one system is better. It is that you should always check which system a number came from before you act on it. The most expensive errors happen when a value looks plausible in both systems, so nothing seems wrong until the material arrives.
Concrete and gravel are ordered by volume, and a cubic yard is about 24 percent smaller than a cubic metre. Order the wrong one for a driveway pour and the second delivery carries a minimum charge that often exceeds the material cost. Paint coverage is quoted per square metre or per square foot depending on the manufacturer, and the two differ by a factor of nearly eleven. Shipping weight brackets are set in either pounds or kilograms, and a parcel that sits just over a threshold can jump an entire price tier. In each case the conversion takes ten seconds and the mistake takes a week to fix.
It depends entirely on what you are measuring, which is the single most common source of baking failures. A cup of granulated sugar weighs about 200 grams, a cup of all purpose flour weighs roughly 120 to 125 grams, and a cup of water weighs about 236 grams. A cup is a measure of volume, not weight, so the answer changes with the density of the ingredient. This is why serious baking recipes list grams rather than cups. Our cooking measurement converter handles the common ingredients so you do not have to guess.
The two systems diverged historically and never reconciled. A US liquid pint is about 473 millilitres while a UK imperial pint is about 568 millilitres, a difference of roughly 20 percent. The same gap applies to gallons, quarts, and fluid ounces. If you are following a British recipe with American measuring cups, or ordering a pint abroad, the difference is large enough to notice. Always check which system a recipe or spec uses before converting.
Subtract 32 from the Fahrenheit value, then multiply by 5 and divide by 9. So 350 degrees Fahrenheit becomes 350 minus 32, which is 318, times 5 divided by 9, which is about 176.7 degrees Celsius. Most recipes round that to 180 degrees Celsius, which is close enough for an oven but not for anything requiring precision. Going the other direction, multiply Celsius by 9, divide by 5, then add 32.
Yes, both are defined exactly rather than approximated. One inch is exactly 2.54 centimetres by international agreement, and one pound is exactly 0.45359237 kilograms. One mile is exactly 1.609344 kilometres. Because these are definitions rather than measurements, you can convert back and forth without accumulating error. Rounding in the middle of a multi step calculation is what introduces mistakes, so convert once at the end rather than at each step.
The United States is the only large economy that has not adopted metric for everyday use, alongside Liberia and Myanmar. Even in the US, metric is standard in science, medicine, the military, and most manufacturing, which means many Americans work in both systems daily without thinking about it. That split is exactly why conversion errors happen: the same document, recipe, or spec sheet can mix units without warning.
They can be expensive. A NASA Mars orbiter was lost in 1999 because one team supplied thrust data in pound force seconds while the navigation software expected newton seconds. On a smaller scale, ordering concrete in cubic yards when you calculated in cubic metres means you are short by about 24 percent, and a second delivery costs more than the first. Converting carefully before you order is the cheapest step in any project.