A quick, free, online unit converter (unit converter calculator) that converts common units of measurement. A unit conversion expresses the same property as a different unit of measurement.
For instance, time can be expressed in minutes instead of hours, while distance can be converted from miles to kilometers, or feet, or any other measure of length.
This is a simple unit converter calculator. Enter the value in the input field, and the calculator will convert it to another unit.
From Metric to U.S. Customary Measures
Unit Converter Calculator – Tools
For example:
Lenght
| Symbol | When You Know | Multiply By | To Find | Symbol |
|---|---|---|---|---|
| mm | millimeter | 0.04 | inch | in |
| cm | centimeter | 0.39 | inch | in |
| m | meter | 3.28 | foot | ft |
| m | meter | 1.09 | yard | yd |
| km | kilometer | 0.62 | mile | mi |
Temperature
| Symbol | When You Know | Calculation | To Find | Symbol |
|---|---|---|---|---|
| °C | Celsius | multiply 1.8, then add 32 | Fahrenheit | °F |
| °K | Kelvin | subtract 273.15 | Celsius | °C |
Weight
| Symbol | When You Know | Multiply by | To Find | Symbol |
|---|---|---|---|---|
| g | gram | 0.04 | Ounce | oz |
| kg | kilogram | 2.20 | pound | lb |
Area
| Symbol | When You Know | Multiply By | To Find | Symbol |
|---|---|---|---|---|
| cm² | square centimeters | 0.16 | square inch | in² |
| m² | square inch | 1.20 | square yard | yd² |
| km² | square kilometer | 0.39 | square mile | mi² |
| ha | hectare (10,000 m2) | 2.47 | acre |
Volume
| Symbol | When You Know | Multiply By | To Find | Symbol |
|---|---|---|---|---|
| mL | milliliter | 0.03 | fluid ounce | fl oz |
| mL | milliliter | 0.06 | cubic inch | in³ |
| L | liter | 2.11 | pint liquid | pt |
| L | liter | 1.06 | quart liquid | qt |
| L | liter | 0.26 | gallon | gal |
| m³ | cubic meter | 35.31 | cubic foot | ft³ |
| m³ | cubic meter | 1.31 | cubic yard | yd³ |
Brief History of the Metric System
In 1668, John Wilkins proposed a decimal system in which length, area, volume, and mass were linked to each other based on a pendulum that had a beat of one second as a base unit of length. In 1670, Gabriel Mouton proposed a decimal system that was instead based on the circumference of the earth.
History of the Pound
In the eighth and ninth centuries of the Common Era (CE), Arab civilization flourished in the Middle East and Spain. The Arabs used coins as a measurement of units of weight since a minted coin could not easily be cut or shaved to reduce its weight, and thus provided a measurable standard. They used a coin called a silver dirhem as a basic measure of weight, which had a weight roughly equivalent to 45 fully grown grains of barley. Ten dirhems comprised a Wukryeh, which was translated into Latin as an “uncia” – the origin of the word “ounce.”
Over time, trade spread from the Mediterranean area to Europe, including the northern German City-States. As a result, a pound, 16 ounces of silver, or 7200 grains, became a commonly used measure in many regions.
While England also adopted this measure, a shortage of silver caused King Offa to reduce the measurement of the pound to 5400 grains in order to use smaller coins. Eventually, when William the Conqueror became King of England, he retained the 5400-grain pound for minting coins but reverted to the 7200-grain pound for other purposes.
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