Unit converter
Type a value, pick two units and see the result and a table of every unit in the group.
Options
This is below absolute zero (−273.15 °C, −459.67 °F, 0 K); nothing real can be that cold. Check the sign.
Raw value:
In every unit
| Unit | Value |
|---|---|
| Millimeter (mm) | – |
| Centimeter (cm) | – |
| Meter (m) | – |
| Kilometer (km) | – |
| Inch (in) | – |
| Foot (ft) | – |
| Yard (yd) | – |
| Mile (mi) | – |
| Nautical mile (nmi) | – |
kB, MB, GB and TB are decimal (1 kB = 1000 B), as on drive labels and mobile plans. KiB, MiB, GiB and TiB are binary (1 KiB = 1024 B), as Windows shows file sizes. Bits are for connection speeds; 8 bits make a byte.
A month is the average Gregorian month of 30.436875 days and a year is 365.2425 days; calendar months and years vary.
US units follow the US customary system (1 gal = 3.785 L, 1 cup = 236.6 mL); UK units follow the imperial system (1 gal = 4.546 L).
Other versions
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Length converter
Millimeters to nautical miles, with a table of every unit as you type. -
Weight converter
Kilograms, pounds, ounces, stones and tonnes, converted as you type. -
Temperature converter
Celsius, Fahrenheit and kelvin in both directions, with the formulas shown. -
Area converter
Square meters, square feet, acres and hectares, converted as you type. -
Volume converter
Milliliters, liters, US and UK gallons, cups and fluid ounces, converted as you type. -
Speed converter
Kilometers per hour, miles per hour, knots, m/s and ft/s, converted as you type. -
Time converter
From nanoseconds to years, converted as you type, with the average month and year stated. -
Data size converter
Bytes, kB, MB, GB, KiB, MiB, GiB and bits, with 1000 and 1024 kept apart.
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Your exact age in years, months and days, from any date of birth. -
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Your body mass index, the WHO adult band and the healthy weight range for your height. -
Percentage calculator
Five percentage questions answered as you type, with the working shown. -
Roman numeral converter
Convert both ways and understand every symbol. -
12-hour to 24-hour converter
Switch between AM/PM and 24-hour time without changing the time. -
Text to Binary
Convert text and byte values in both directions, using ASCII or UTF-8.
Pick a quantity, type a value and choose the units on each side; the result updates as you type, and a table below shows the same value in every unit of that group. The converter covers length, weight, temperature, area, volume, speed, time and data size, with the exact factors from the definitions (an inch is 2.54 cm, a pound is 0.45359237 kg). Decimal commas and points both work, the result is formatted for your language, and the raw value next to it is plain ASCII you can paste into a spreadsheet or code. Everything runs in the page: nothing is sent anywhere, and your last conversion stays on this device.
How to use
- Choose a quantity such as length or weight.
- Type the value; a comma or a point both work as the decimal separator.
- Pick the unit you have and the unit you want, or press the swap button to reverse them.
- Read the result, copy the raw value, or find any other unit in the table below.
- Change the precision if you need fewer or more significant digits.
What it handles
- Accepts 1,5 and 1.5, grouping spaces such as 12 500, and exponent notation such as 2.5e6.
- Shows the result in your locale’s number format and the raw value as plain digits with a point, ready to paste.
- Rounds to 3 to 12 significant digits (10 by default), with no floating-point tails such as 3.2808398950000003.
- The table lists the value in every unit of the group and highlights the unit you started from.
- Remembers the quantity, the unit pair and the value on this device, and puts them in the address so a copied link repeats the conversion.
FAQ
Which units does the converter include?
Nine length units from millimeters to nautical miles, eight weight units including stones and US tons, Celsius, Fahrenheit and kelvin, eleven area units, fifteen volume units covering metric, US customary and UK imperial, five speed units, ten time units from nanoseconds to years, and thirteen data units in decimal, binary and bits. Each group has its own page, linked below.
Can I type a decimal comma?
Yes. 1,5 and 1.5 both mean one and a half, in every language. Spaces and apostrophes used as thousands separators are ignored, so 12 500 and 12’500 are read as twelve and a half thousand. If a value contains both a comma and a point, the last one is treated as the decimal separator, which is how 1.234,5 and 1,234.5 are written in different countries.
How accurate are the results?
The factors are the defined ones: an inch is exactly 25.4 mm, a pound exactly 0.45359237 kg, a US gallon exactly 3.785411784 liters. The arithmetic is double-precision floating point, and the result is rounded to the number of significant digits you choose, ten by default. Only the average month and year are approximations, and the time page says which values they use.
Is anything uploaded or stored?
Nothing is uploaded; the conversion is a multiplication done in your browser, and the page keeps working with the connection off. Your last quantity, unit pair, value and precision are kept in this browser’s storage on this device so they are back when you return. Clear removes the value, and clearing the browser’s site data removes the rest.
What is the raw value for?
The big result is formatted for your language, with a decimal comma and grouping where that is the convention. The raw value under it is the same number as plain digits with a point and no grouping, so it pastes into a spreadsheet or code without cleanup. The Copy button and Ctrl+Shift+C copy the raw value; clicking the result card copies the formatted one.
Updated