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Engineering unit converter
Force, pressure, torque, power, energy, flow and the rest of the everyday mechanical quantities — with the whole family listed underneath so you can read across at a glance.
Quantity
To
1 ft = 0.3048 m
All length unitsbase: m
| Unit | Symbol | Value |
|---|---|---|
| Millimetre | mm | 304.8 |
| Centimetre | cm | 30.48 |
| Metre | m | 0.3048 |
| Kilometre | km | 0.0003048 |
| Inch | in | 12 |
| Foot | ft | 1 |
| Yard | yd | 0.3333333333 |
| Mile | mi | 0.0001893939394 |
| Thou (mil) | thou | 12000 |
Questions
How accurate are these conversions?
Factors are exact wherever the definition is exact — an inch is exactly 25.4 mm and a pound-force is exactly 4.4482216152605 N, for instance — and otherwise use the standard accepted value. Results are shown to ten significant figures, switching to exponential notation at very large or very small magnitudes so nothing rounds away to zero.
Why is temperature handled differently?
Every other quantity here is a pure scale, so converting is a single multiplication. Temperature scales have different zero points as well as different step sizes, so Celsius, Fahrenheit, Kelvin and Rankine are converted through kelvin with an explicit offset rather than a factor.
What is the difference between mechanical and metric horsepower?
Mechanical horsepower is defined as 550 foot-pounds per second, about 745.7 W, and is the figure normally quoted in the US and UK. Metric horsepower (PS) is about 735.5 W and is common in European vehicle specifications. The roughly 1.4% difference matters when comparing quoted outputs.
Does it convert between different quantities?
No, and deliberately so. Converting mass to force, or pressure to head, needs extra physical context such as gravity or fluid density. Silently assuming a value would produce confident but wrong numbers, so each quantity is kept separate.