Unit Converter Online Free — Length, Weight, Temperature & More
Convert between units of length, weight, temperature, area, volume, speed, data and time.
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How to Convert Units Online
- 1
Choose a category
Select a unit category: Length, Weight, Temperature, Area, Volume, Speed, Data, or Time.
- 2
Enter your value
Type a value in the From field and select the unit to convert from.
- 3
Select target unit
Select the To unit. The converted result appears instantly.
Unit conversion errors have crashed a Mars orbiter and grounded the "Gimli Glider" — when NASA and Air Canada can get metric-imperial conversion wrong, a recipe or a workout plan certainly can. This converter covers the eight categories that come up in daily life and work — length, weight, temperature, area, volume, speed, data, and time — with exact standard factors rather than rounded rules of thumb.
Temperature is the special case:every other conversion is a multiplication, but Celsius, Fahrenheit, and Kelvin scales have different zero points, so the formula involves an offset — the reason "double it and add 30" is only an approximation. This tool applies the exact formulas, and it is the one category where negative values are meaningful.
Data units deserve their asterisk:storage marketing uses decimal units (1 GB = 1,000 MB) while operating systems traditionally report binary ones (1 GiB = 1,024 MiB) — the entire reason a "500 GB" drive shows up as 465 GB in Windows. The data category converts within the decimal convention, matching how bandwidth and storage are sold.
Practical pairings: cooking (cups to millilitres, oven Fahrenheit to Celsius), fitness (miles to kilometres, pounds to kilograms), shipping (dimensional weight in both systems), and development (megabits vs. megabytes when someone quotes a connection speed). For conversions involving money rather than measures, the currency converter handles the 150+ currencies this tool deliberately leaves out.