How do you convert feet to millimeters?
Multiply by 304.8. That's exact, because a foot is defined as 0.3048 m.
An 8 ft by 4 ft sheet of plywood works out at 2,438.4 by 1,219.2 mm, which is why UK sheets sold as 2,440 by 1,220 mm still fit framing laid out in feet.
For a rough figure, call a foot 300 mm. It's 1.6% low – fine for a garden shed, not for a kitchen worktop.
What is a foot?
The foot is an imperial and US unit of length equal to 12 inches, or exactly 30.48 centimeters. It is a third of a yard and 1/5,280 of a mile.
The foot began as the length of a human foot, and so differed from place to place and from person to person. The modern international foot was fixed at exactly 0.3048 meters by agreement in 1959.
People's height is given in feet and inches in the US and UK, and aircraft altitude is given in feet nearly everywhere, metric countries included.
What is a millimeter?
A millimeter is a thousandth of a meter (1/1000) which is the SI (International System of Units) unit of length. It is normally used to measure small lengths like the thickness of a sheet of paper or the dimensions of a small object.
One millimeter is approximately equal to 0.03937 inches (about 1/25th). Presicely there are 25.4 millimeters in an inch and it is often used in science and engineering. It is used in countries that have adopted the metric system.
You may come across millimeters when measuring the size of electronic components, jewelry or even the thickness of a fingernail.