Unit Converter
Quickly convert measurements like length, weight, temperature, area and volume.
The unit converter translates measurements between the metric and imperial systems across five categories: length, weight, temperature, area and volume. It's useful for situations like following a US recipe, understanding a technical spec given in inches, working out a distance in miles, or converting a foreign weather forecast's temperature. Pick the category, type the value, and select the source and target units to see the converted result automatically.
How to use
- Choose the measurement category: length, weight, temperature, area or volume.
- Type the value and select the source and target units.
- Use the swap button to quickly flip the direction of the conversion.
Worked example
Someone planning a 5-mile race (a common distance in US and UK events) wants to know the metric equivalent. In the "Length" category, selecting "Mile" as the source unit and "Kilometer" as the target, 5 miles works out to 8.047 km. Similarly, seeing that another country's forecast calls for 100°F, selecting "Fahrenheit" to "Celsius" in the "Temperature" category shows that's 37.78°C — much hotter than the number "100" alone suggests to anyone used to the metric system.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius temperature by 9/5 and add 32. For example, 20°C equals (20 × 9/5) + 32 = 68°F.
What's the difference between an ounce (weight) and a fluid ounce (volume)?
An ounce (oz) measures mass/weight and is used for solids, while a fluid ounce (fl oz) measures the volume of liquids. Despite the similar name, one doesn't convert directly into the other without accounting for the material's density.
Do the area and volume conversions use the metric or imperial system?
Both: each category mixes metric units (like square meters and liters) with imperial ones (like acres and gallons), so you can convert freely between the two systems.
Why does the US still use miles, pounds and Fahrenheit?
It's largely historical: the US never officially adopted the International System of Units (metric) for everyday use, unlike most of the world. That makes frequent conversions necessary for anyone dealing with US recipes, products, construction measurements, or weather forecasts.
What's the difference between a metric ton and other tons?
This calculator uses the metric ton (1,000 kg), the most common international standard. Other variants exist, like the US short ton (about 907 kg) and the UK long ton (about 1,016 kg), which aren't the same and can cause confusion in international trade contexts.
Why isn't 1 liter always exactly 1,000 cubic centimeters in every calculator I've seen?
For virtually all practical purposes, 1 liter is exactly equal to 1,000 cm³ (or 1 dm³) — that's been the official definition since 1964. Small discrepancies that show up in some older calculators come from a slightly different historical definition of the liter used between 1901 and 1964, no longer in use today.