Unit Converter
Convert between any units of measurement instantly.
All Unit Converters
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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This universal converter handles 10 categories of measurement: length, weight, temperature, volume, speed, area, data storage, pressure, energy, and fuel economy. You can use it in two ways.
- Smart mode. Type a value and unit into the Quick Convert field at the top. For example, type "5 miles" or "200 lbs" and the tool will automatically detect the unit, select the right category, and show conversions to every other unit in that category.
- Manual mode. Pick a category from the dropdown, enter a numeric value, then choose the "From" and "To" units. The result updates instantly as you type or change selections.
- Swap direction. Click the arrow button between the From and To dropdowns to reverse the conversion without retyping anything.
- Copy or share. Use the Copy button to grab the result, or the Share button to generate a link with your conversion pre-filled so you can send it to someone.
Below the primary result, a grid shows the value converted to all other units in the same category at once, so you can compare multiple units side by side.
About Unit Conversion
The world uses two main systems of measurement. The metric system (SI), adopted by most countries, is built on base-10 relationships: 1,000 millimeters in a meter, 1,000 meters in a kilometer. The imperial system, still common in the United States and parts of the United Kingdom, uses more varied relationships: 12 inches in a foot, 3 feet in a yard, 5,280 feet in a mile.
This converter works by translating your input into a base unit for each category (meters for length, kilograms for weight, pascals for pressure, and so on), then converting from that base unit to the target. Temperature and fuel economy use direct formulas instead, since they involve offsets or inverse relationships rather than simple multiplication.
All conversion factors follow internationally agreed definitions. The results are calculated entirely in your browser with no data sent to any server.
Frequently Asked Questions
What units can I convert?
This tool supports 10 categories: length (mm, cm, m, km, in, ft, yd, mi), weight (mg, g, kg, oz, lb, st, ton), temperature (Celsius, Fahrenheit, Kelvin), volume (ml, l, gal, qt, pt, cup, fl oz, tbsp, tsp), speed (m/s, km/h, mph, knots, ft/s), area (mm2 through hectares and acres), data storage (bytes through petabytes), pressure (Pa, kPa, bar, psi, atm, mmHg), energy (J, kJ, cal, kcal, Wh, kWh, BTU), and fuel economy (mpg, km/l, l/100km).
How does the smart input work?
The smart input field parses natural text like "5 miles," "200 lbs," or "100 km/h." It extracts the number and matches the unit text against a list of common abbreviations and full names. Once detected, it automatically selects the correct category and unit, then shows the conversion to all other units in that category.
Are the conversions accurate?
Yes. All conversion factors use internationally defined values. For example, one inch is exactly 25.4 mm, one pound is exactly 0.45359237 kg, and one atmosphere is exactly 101,325 Pa. Results are displayed with up to 6 significant digits. The calculations run entirely in your browser using standard floating-point arithmetic.
Can I convert temperature?
Yes. Select the Temperature category, then choose from Celsius, Fahrenheit, or Kelvin. Temperature conversions use direct formulas (for example, F = C x 9/5 + 32) rather than simple multiplication, since the scales have different zero points. You can also type "100 fahrenheit" or "37 celsius" in the smart input field.