The exact factor, and the one you can do in your head
For a fast estimate, multiply newton-metres by 0.74 (or foot-pounds by 1.36). The pair worth memorising is 100 Nm ≈ 74 ft-lb. This is a pure unit conversion, so it holds for any torque value.
Quick reference
| Newton-metres | Foot-pounds | Foot-pounds | Newton-metres |
|---|---|---|---|
| 10 Nm | 7.4 ft-lb | 10 ft-lb | 13.6 Nm |
| 25 Nm | 18.4 ft-lb | 25 ft-lb | 33.9 Nm |
| 50 Nm | 36.9 ft-lb | 50 ft-lb | 67.8 Nm |
| 100 Nm | 73.8 ft-lb | 100 ft-lb | 135.6 Nm |
| 150 Nm | 110.6 ft-lb | 150 ft-lb | 203.4 Nm |
| 200 Nm | 147.5 ft-lb | 200 ft-lb | 271.2 Nm |
Handy for reading torque specs: European service manuals list Nm, US ones list ft-lb. Common wheel-nut torque is 100 to 140 Nm, which is 74 to 103 ft-lb.
The gotcha: the numbers are not interchangeable
100 Nm and 100 ft-lb are not the same tightness — treating one as the other leaves you about 35% off. On a wheel nut or head bolt that is the gap between a safe joint and a stripped thread or a wheel that works loose.
Set to the same number on the wrong scale, a foot-pound spec is about 36% more torque than the newton-metre one. Always match the unit the spec is written in.
Common questions
How many foot-pounds is 100 Nm?
100 Nm is 73.76 ft-lb. A quick mental estimate is to multiply the newton-metres by 0.74.
How many newton-metres is 100 ft-lb?
100 ft-lb is 135.58 Nm. Going the other way, multiply the foot-pounds by about 1.36.
Are newton-metres and joules the same thing?
They share the same units, but they describe different things. A newton-metre of torque is a twisting force around an axis; a joule is energy, a force acting over a distance. By convention torque is written N·m and energy is written J.
