Unit Converter
Convert length, weight and temperature between metric and imperial units instantly.
Pick a category — length, weight, or temperature — enter a value, and get the converted result immediately as you type. Common units like metres, feet, kilograms, pounds, Celsius and Fahrenheit are all supported, so it works for everyday conversions like recipe measurements, travel distances, or checking a temperature in another unit.
Why the US still confuses everyone else with units
The United States is one of the few countries that still primarily uses imperial units (feet, pounds, Fahrenheit) in daily life, while most of the world uses metric. This makes unit conversion a genuinely common need — reading a US recipe as a metric cook, checking a US clothing size chart, or understanding a US weather forecast in Fahrenheit when you think in Celsius. This tool exists specifically to bridge that everyday gap without needing to remember conversion formulas.
Temperature conversion works differently from length and weight
Unlike length or weight, where converting is just multiplying by a fixed factor, temperature scales don't share a common zero point — 0°C is not the same physical temperature as 0°F. Converting requires first shifting to account for the different starting points before scaling, which is why Celsius to Fahrenheit uses the formula (C × 9/5) + 32 rather than a simple multiplication like length units use.
Precision matters more in some fields than others
For a recipe or a rough travel-distance estimate, rounding to one or two decimal places is more than enough. But for engineering, medical dosing, or scientific work, small rounding errors in unit conversion can compound into meaningful mistakes — those fields typically use dedicated, domain-specific conversion tables rather than general-purpose converters like this one.
How to use it
- Choose a category: length, weight, or temperature.
- Select your 'from' and 'to' units.
- Type a value in the input field.
- The converted value appears instantly on the right.
Common ways people use this tool
Cooking from an international recipe
Convert a recipe's grams or Celsius oven temperature into cups and Fahrenheit, or the reverse.
Understanding travel distances abroad
Convert kilometres shown on a foreign road sign or map into miles you're more familiar with.
Checking weather forecasts in another unit
Quickly convert a Fahrenheit forecast into Celsius or vice versa when travelling or reading international news.
Tips for getting the best results
- Double-check which direction you're converting — it's an easy mistake to swap 'from' and 'to' units, especially with temperature.
- Use the swap button to quickly flip a conversion without re-entering units manually.
- For cooking, remember that weight-to-volume conversions (like grams of flour to cups) vary by ingredient density — this tool only converts within the same measurement type.
- Round sensibly for everyday use — a fitness tracker or grocery scale rarely needs more than one decimal place of precision.
Frequently asked questions
Which units are supported?
Length supports metres, kilometres, centimetres, millimetres, feet, inches and miles; weight supports kilograms, grams, pounds and ounces; temperature supports Celsius, Fahrenheit and Kelvin.
Is the conversion precise enough for cooking or science?
Results are calculated to several decimal places using standard conversion factors, which is precise enough for cooking, DIY, and most everyday science use.
Can I convert in both directions?
Yes, use the swap button to instantly flip the 'from' and 'to' units.
Why is 0°C not 0°F?
The two scales have different zero points by design — Fahrenheit was originally calibrated using a different reference than Celsius, which is why the conversion formula includes both a multiplication and an addition step.
Can I convert volume units like litres or gallons?
This version focuses on length, weight and temperature; volume conversion may be added as a future tool.
Is Kelvin the same size step as Celsius?
Yes — a one-degree change in Kelvin equals a one-degree change in Celsius; only the starting point (0 K equals absolute zero) differs.
Does the tool round results?
Yes, results are rounded to a reasonable number of decimal places for readability, while still being precise enough for everyday and most professional uses.
Why do recipe conversions between cups and grams sometimes seem inconsistent across sources?
Volume-to-weight conversion depends on the specific ingredient's density — a cup of flour and a cup of sugar weigh different amounts — so a general length/weight converter like this one intentionally doesn't attempt ingredient-specific volume conversions, which need a dedicated cooking conversion reference instead.
Is there a difference between a UK and US measurement for the same unit name?
Yes in some cases — a US gallon and UK imperial gallon differ in size, for example, though the length, weight and temperature units offered here are standard and consistent internationally.
Why does converting a very small or very large number sometimes show scientific notation elsewhere but not here?
This tool displays results as plain decimal numbers rather than scientific notation, which keeps results easy to read directly, though extremely large or small values may show many decimal places as a result.
Is a metric ton the same as an imperial ton?
No, a metric tonne (1000 kg) and an imperial/US ton differ in size — this converter's weight units currently focus on the more everyday kilogram, gram, pound and ounce range rather than the larger ton units.