Unit Converter: Length, Weight, Temperature & More
Recipes, DIY plans and science homework constantly switch between metric and imperial units. This unit converter handles length, weight, temperature, area, volume and speed, so you can move between systems without looking up factors each time. Accurate conversion factors keep results suitable for both casual projects and technical checks.
Please enter a valid number.
How to Use the Unit Converter
- Choose a category: length, weight, temperature, area, volume or speed.
- Select the unit you are converting from and the unit you want as the result.
- Enter the numeric value to convert.
- Select Convert. To go the other way, switch the From and To units.
Pick the category first, because the From and To lists change with it. Then enter your value and choose the two units. The result appears with the unit name and is rounded to at most four decimal places. Temperature uses formulas instead of a single factor, so it follows the same steps but a different calculation.
Unit Converter Formula Explained
Conversions multiply by an exact or high-precision factor. By definition, 1 inch equals 0.0254 metres exactly. One foot equals 0.3048 metres, one yard equals 0.9144 metres, and one international mile equals 1609.344 metres. Using the international foot avoids older survey-foot discrepancies. Temperature uses formulas instead: °F = °C × 9/5 + 32 and K = °C + 273.15. Keep units consistent when chaining conversions so rounding errors do not accumulate.
Apart from temperature, the calculator converts your value to a base unit (metre, kilogram, square metre, litre or metre per second) and then to the unit you chose. Results show up to four decimal places, so very small values may look rounded. The factors for km/h and knots are rounded, so speed results can differ from other converters in the last decimal place.
Unit Converter Example Calculation
1.80 m equals about 5 ft 11 in. 90 km/h is roughly 56 mph. Product specs and instructions often mix metric and imperial units, and this converter helps when they do.
Worked example: choose Length, enter 1.8 and convert from m to ft. The result is 5.9055 ft. Choose Temperature, enter 100 and convert Celsius to Fahrenheit for 212 Fahrenheit. Choose Weight and convert 70 kg to lb for 154.3236 lb. Choose Speed and convert 90 km/h to mph for 55.9235 mph.
When to use this tool
Use this for DIY manuals, travel, science coursework and product specs that mix metres, centimetres, feet and inches.
Key Features & Benefits of This Unit Converter
- Six categories, 30 units — length, weight, temperature, area, volume and speed.
- Exact international factors — for example 1 inch is exactly 0.0254 m and 1 mile is exactly 1,609.344 m.
- Temperature by formula — Celsius, Fahrenheit and Kelvin use conversion formulas instead of a single factor.
- Results to four decimals — switch the From and To units to convert the other way.
- Instant, free and private — runs entirely in your browser, no sign-up, nothing stored.
Good to know
Construction and product standards in the EEA are predominantly metric. Keep a conversion handy when working with US or UK imperial documentation on imported goods. For engineering tolerances, prefer exact SI factors rather than rounded mental conversions. Always double-check critical measurements when safety or compliance is involved.
Unit Converter — FAQs
Are the factors exact?
The inch–metre relationship is defined as exact. Other factors follow international standards used in science and trade.
Can I convert area or volume?
Yes. Choose Area or Volume in the category list. Area covers m², km², ft², acres and hectares. Volume covers litres, millilitres, US gallons, US quarts and cups.
Why do some converters disagree slightly?
Rounding of intermediate factors or use of survey feet versus international feet can create tiny differences. This tool uses the international foot.
Does it convert temperature or weight?
Yes. Choose Temperature (Celsius, Fahrenheit and Kelvin) or Weight (kg, g, mg, lb and oz) in the category list.