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0.001

1 m (SI) = 0.001 km (SI)

SI uses kB = 1000 B; IEC uses KiB = 1024 B. Temperature is bounded at absolute zero.

How to convert length, weight, data size, and temperature

Unit Converter handles four kinds of quantity — length, weight, data size, and temperature — and converts as you type, with no button to press and nothing sent to a server. Data size is the part most converters get wrong, so the page lets you choose between SI units where a kilobyte is 1000 bytes and IEC units where a kibibyte is 1024, and shows the symbol it used. Temperature conversions go through kelvin and refuse any value that would fall below absolute zero.

Convert a value in four steps

  1. Pick the categoryChoose length, weight, data size, or temperature. The unit menus are refilled with the units that belong to that category, so a conversion between incompatible quantities cannot be selected by accident.
  2. Choose the from and to unitsLength offers m, km, cm, mm, mi, ft, and in. Weight offers kg, g, lb, and oz. Temperature offers Celsius, Fahrenheit, and kelvin. The swap button exchanges the two units when you picked them the wrong way round.
  3. Type the value and read the resultEnter a decimal number, including scientific notation such as 1.5e3 if you like. The result appears immediately with up to twelve significant digits and its own copy button.
  4. For data size, choose SI or IECThe data category adds a second control: IEC gives you KiB, MiB, GiB, and TiB in powers of 1024, while SI gives kB, MB, GB, and TB in powers of 1000. Pick the one whose definition the number you are checking was written with.

What people use Unit Converter for

  • Reconcile a disk size that looks wrongA drive sold as 1 TB shows as about 931 GiB. Convert between the SI and IEC families to see exactly where the missing space went.
  • Work with a spec written in other unitsTurn inches into millimetres or pounds into kilograms while reading a datasheet, a shipping form, or a hardware spec.
  • Check a temperature from a foreign forecastConvert Fahrenheit to Celsius, or either to kelvin when you need the value in the units a scientific formula expects.
  • Size an upload or a quotaConvert a byte count into MB or MiB to check it against a limit that a service states in one family or the other.

Unit Converter questions

Is a kilobyte 1000 or 1024 bytes?
Both definitions are in use, which is why the page makes you choose. SI says a kilobyte is 1000 bytes; the IEC names — kibibyte, mebibyte, gibibyte — are the unambiguous ones for powers of 1024.
Why does my 1 TB drive show as 931 GB?
The manufacturer counted in SI terabytes of 1000 bytes each and the operating system displayed gibibytes of 1024 bytes each, while still writing GB. Converting 1 TB to GiB gives about 931, so no space is actually missing.
Are my values sent to a server?
No. The conversion runs entirely in this browser tab, so nothing you type is uploaded or stored.
What happens below absolute zero?
The conversion is refused and the page says so. Minus 300 Celsius does not correspond to a physical temperature, so returning a number for it would be worse than reporting the problem.
How precise is the result?
Up to twelve significant digits, computed in double-precision floating point through a single base unit per category. That is more precision than a measurement in these units normally carries.
Can it convert currency?
No. Currency conversion needs a live exchange rate, and this page holds only fixed physical unit definitions. Area, volume, and speed are not included either.