To convert feet to millimeters (ft to mm), multiply by 304.8. 1 foot equals 304.8 mm, about 44% of a tennis racket.
| feet | millimeters |
|---|---|
| 1 foot | 304.8 mm |
| 2 feet | 609.6 mm |
| 5 feet | 1,524 mm |
| 10 feet | 3,048 mm |
| 25 feet | 7,620 mm |
| 50 feet | 15,240 mm |
| 100 feet | 30,480 mm |
| 250 feet | 76,200 mm |
| 500 feet | 152,400 mm |
| 1000 feet | 304,800 mm |
Definition: 12 inches, or exactly 0.3048 meters.
History: The foot traces back to the Roman "pes," and different versions of it were used across Greek, Roman, English, Chinese, and French systems, each a slightly different length depending on who was measuring. English legend credits King Henry I with standardizing it in the 12th century using his own foot as the template - likely a booted foot, since people (and their footwear) tended to run smaller back then. It took until 1959 for the US, UK, and four other countries to finally agree on one exact, shared definition.
Current use: Building and construction measurements, room dimensions, and aircraft altitude are still commonly given in feet, even in countries that otherwise use metric.
Definition: 1/1000 of a meter - the same "milli" prefix as milliliter or milligram.
History: Like the centimeter, it arrived as part of the same 1790s French decimal system, built specifically to make precise, small-scale measurement simple - no more converting between competing local systems of inches, lines, and points.
Current use: Engineering tolerances, screen and camera specs, and rainfall measurements - which is why weather reports outside the US say "20mm of rain" rather than inches.
The factor is 304.800, which is derived rather than defined, so any decimal you see has been rounded somewhere.
No simple round multiplier is close enough to be useful, so this is one to look up rather than estimate. The exact factor is 304.800.
Going the other way, one millimeter is 0.0032808 ft. Because the numbers get large quickly, a whole-number answer is almost always enough here: carrying decimals implies a precision your original measurement probably does not have.
To anchor the scale: 1 foot is about 305 mm.