Unit Converter

Common questions

Why does it show every unit instead of just the one I asked for?

The list shows the other common units in the selected category; turn on Uncommon units to include the remaining entries. The From unit is omitted because its value is already in the input box. You can select any listed unit as the headline target, including an uncommon unit while the list switch is off.

Why do so many converters get temperature wrong?

Because Celsius and Fahrenheit do not share a zero point. Most conversions are a simple ratio, since a kilometre is always 1,000 metres, but temperature needs a multiplication and an offset. A converter built only on ratios reports 0 °C as 0 °F. This one stores an offset alongside every factor, so the affine cases come out right.

Is a kilobyte 1,000 bytes or 1,024?

A kilobyte (kB) is 1,000 bytes; a kibibyte (KiB) is 1,024 bytes. Both are listed with distinct names, as are MB/MiB, GB/GiB and TB/TiB. A 1 TB quantity is about 931.322574615 GiB and remains exactly 1,000 GB. Some software uses a GB label for a binary GiB count, while other software uses decimal units; the label alone does not establish its convention.

Are US and imperial measures the same?

US and imperial volume measures differ. A US gallon is exactly 3.785411784 liters and an imperial gallon exactly 4.54609 liters, about 20% larger. Their pints and fluid ounces also differ. Both are labeled in the menus; imperial rows are included when Uncommon units is on. The spoon and cup entries use US customary definitions, which differ from metric or Australian recipe measures.

How precise are the results?

The converter calculates from the written decimal using bounded rational arithmetic and rounds the display to 12 significant digits, with trailing zeros removed. Exact definitions such as 1 inch = 2.54 cm and 1 pound = 0.45359237 kg do not make every displayed result exact: repeating fractions and longer values are rounded. Inputs must have a finite numeric magnitude and at most 512 significant digits; nonzero values too small to represent as numeric input are refused instead of becoming zero. The listed conventions identify approximate coefficients, including psi and parsec.

What can I type in the box?

A number such as 1234.5, 1,234.5 or 1 234.5, with a minus sign for negatives (a typeset −40 works too), and the From unit after it if you like, such as 5 ft or 98.6 °F. A comma only separates thousands, so 1,5 is refused with a note instead of being read as 15: type 1.5. If the unit you type is a different one, the page says which to pick under From. Scientific notation, +5, .5 and 5. are accepted. Fractions, decimal commas, clock strings and compound measurements such as 5 ft 2 in are not numeric inputs here.

Is anything sent to a server?

Your input and converted values are calculated in the browser and are not uploaded by the converter. The unit definitions arrive with the page; conversion needs no external data lookup and keeps working offline after the page has loaded.

How do I convert hours and minutes into seconds?

This converter takes a numeric value in one unit. For 2 hours 30 minutes, select Time, enter 2.5 hours, and read 9000 seconds. For a longer mixed list, use Time Calculator to get the total in minutes, then enter that numeric result here with Minute selected and read Second. A clock string such as 2:30 is not a numeric input here.

What does the converter remember?

When browser storage is available, valid deliberate changes save the edited settings after a short delay. Restoring saved settings is read-only, and invalid or incomplete drafts do not replace them. A focused conversion page opens on its named unit pair and preserves the main converter’s saved pair; a saved value and uncommon-unit preference can travel between pages. If an older, unusable or conflicting record cannot be updated, the page explains this and keeps it until you use Forget saved settings. Forgetting removes the saved record while keeping the current conversion on screen.