100 N·m in lbf·ft
- Value
- 100 N·m
- From
- newton-metre (N·m)
- To
- pound-foot (lbf·ft)
- Converted value
- 73.7562149277 lbf·ft
Checked against: 100 / (4.4482216152605 × 0.3048)
Torque converter (N·m, lb-ft)
Convert N·m to lb-ft, lb-ft to N·m, lb-in and kgf·m for torque wrench and bolt specifications, using 1 lbf·ft = 1.3558179483314004 N·m exactly.
By AdminDrafted with AI writing toolsUpdated Checked examples: 4
Converted value
lbf·ft
Converted value: 73.7562149277 lbf·ft
- Conversion
- 100 N·m ≈ 73.75621 lbf·ft
- Conversion factor
- 0.737562149277
- Exactness
- Exact definitions, repeating decimal
100 N·m is about 73.75621 lbf·ft. One newton-metre is about 0.7375621 lbf·ft.
The same amount counted in each unit
100 N·m in every Torque unit
| Unit | Value | Definition |
|---|---|---|
| newton-metre (N·m) | 100 | Base unit |
| kilonewton-metre (kN·m) | 0.1 | 1 kN·m = 1,000 N·m, exact |
| pound-foot (lbf·ft) | 73.75621 | 1 lbf·ft = 1.3558179483314004 N·m, exact |
| pound-inch (lbf·in) | 885.0746 | 1 lbf·in = 0.1129848290276167 N·m, exact |
| kilogram-force metre (kgf·m) | 10.19716 | 1 kgf·m = 9.80665 N·m, exact |
How it's calculated S
Convert newton-metre to pound-foot
1 lbf·ft = 1.3558179483314004 N·m, exact
Both units are defined exactly, but the converted value is a repeating decimal; it is shown to 12 significant figures.
About the torque converter
Torque is force times the perpendicular lever arm, so every torque unit is a force unit multiplied by a length unit, held here as newton-metres. One pound-foot is 4.4482216152605 N × 0.3048 m = 1.3558179483314004 N·m exactly, a pound-inch is a twelfth of that, and a kilogram-force metre is 9.80665 N·m.
The default converts 100 N·m to 73.756 lbf·ft, the scale of wheel-nut and engine torque figures. Bicycle parts and small fasteners use smaller values: 5 N·m is 44.25 lbf·in.
Torque and energy share the dimension N·m, but NIST SP 811 specifies the newton metre, not the joule, as the unit of moment of force, so a torque is never written in joules.
How to convert N·m to lb-ft
The shortened multipliers and displayed converted decimals below are approximate; the complete force-and-length definitions are exact.
Multiply newton-meters by 0.737562, or divide by 1.355818: 100 N·m = 73.76 lb-ft. The exact link is 1 lbf·ft = 4.4482216152605 N × 0.3048 m = 1.3558179483314004 N·m. Use it for engine torque, wheel-nut and torque-wrench settings quoted in the other system of units.
Both factors are exact: the pound-force comes from the 1959 pound and standard gravity, and the foot from the 1959 yard. Their product is exact too (NIST SP 811, Appendix B.9).
How to convert lb-ft to N·m
Multiply pound-feet by 1.355818. So 80 lb-ft is 108.47 N·m and 150 lb-ft is 203.37 N·m. Going the other way, a 120 N·m setting is 88.51 lb-ft.
Engine torque is quoted in N·m in Europe and in lb-ft in the US: a 400 N·m engine makes 295.02 lb-ft, and 250 N·m is 184.39 lb-ft.
lb-in (in-lb) to N·m
A pound-inch is one twelfth of a pound-foot, 0.112985 N·m, and 1 N·m is 8.850746 lbf·in. Small fasteners are specified in lbf·in or N·m: 5 N·m is 44.25 lbf·in, and 50 lbf·in is 5.65 N·m.
kgf·m (kg·m) to N·m
Older workshop manuals give torque in kilogram-force meters, often written kg·m or kgm. 1 kgf·m = 9.80665 N·m exactly, so 10 kgf·m is 98.07 N·m or 72.33 lb-ft.
lb-ft or ft-lb?
Both name the same size, 1.3558 N·m. Engineering usage writes pound-foot (lbf·ft) for torque and foot-pound (ft·lbf) for work; workshop manuals often write ft-lb for torque, with the same number.
The split mirrors SI practice: NIST SP 811 lists torque under moment of force in newton-meters, apart from energy in joules. A torque of 1 N·m turning through one full revolution does 2π J of work.
Torque conversion chart
Repeating decimals are rounded to six places.
| Value | From | To | Converted torque |
|---|---|---|---|
| 100 | N·m | lbf·ft | 73.756215 |
| 1 | lbf·ft | N·m | 1.355818 |
| 12 | lbf·in | lbf·ft | 1 |
| 1 | kgf·m | N·m | 9.80665 |
| 5 | N·m | lbf·in | 44.253729 |
| 1 | kN·m | N·m | 1000 |
Torque to horsepower needs rpm
Torque alone gives no power. The denominator in the following horsepower relation is rounded. In US units, hp = lb-ft × rpm ÷ 5,252, where 5,252 is 33,000 ÷ 2π. In SI, power in watts is torque in N·m times angular speed in rad/s.
Common mistakes
- Mixing lb-in and lb-ft. They differ by a factor of 12: setting 10 lb-ft for a 10 lb-in spec applies 12 times the intended torque.
- Writing torque in joules. Use N·m for torque and J for energy, even though the dimensions match.
- Reading kg·m as a mass. A kgf·m is a force times a length, 9.80665 N·m.
Related torque tools
For one direction at a time, use N·m to lb-ft or lb-ft to N·m. The horsepower calculator turns torque and rpm into horsepower, and the force converter handles the force on its own.
Worked examples
1 lbf·ft in N·m
- Value
- 1 lbf·ft
- From
- pound-foot (lbf·ft)
- To
- newton-metre (N·m)
- Converted value
- 1.35581794833 N·m
- Exactness
- Exact
Checked against: 4.4482216152605 N × 0.3048 m = 1.3558179483314004 N·m (NIST SP 811 App. B)
12 lbf·in is 1 lbf·ft
- Value
- 12 lbf·in
- From
- pound-inch (lbf·in)
- To
- pound-foot (lbf·ft)
- Converted value
- 1 lbf·ft
Checked against: 12 in = 1 ft
1 kgf·m in N·m
- Value
- 1 kgf·m
- From
- kilogram-force metre (kgf·m)
- To
- newton-metre (N·m)
- Converted value
- 9.80665 N·m
Checked against: 9.80665 N × 1 m
Questions
How do I convert N·m to lb-ft?
Multiply by approximately 0.737562, or divide by approximately 1.35582. 100 N·m is about 73.76 lbf·ft, and a 120 N·m wheel-nut setting is about 88.51 lbf·ft. The factor comes from 1 lbf·ft = 4.4482216152605 N × 0.3048 m, which is exact; the displayed factors and worked values are rounded where needed.
Is lb-ft the same as ft-lb?
They are the same size, 1.3558 N·m. By convention the pound-foot (lb-ft, lbf·ft) is used for torque and the foot-pound (ft-lb, ft·lbf) for work or energy, mirroring the SI split between N·m for torque and joules for energy. In everyday use “ft-lb” is often written for torque too, and the number is the same.
How do I convert lb-in to N·m?
Multiply by 0.112985. A pound-inch is one twelfth of a pound-foot, so 12 lbf·in = 1 lbf·ft ≈ 1.3558 N·m. Small fasteners are specified in lbf·in or N·m: 50 lbf·in is 5.65 N·m, and 5 N·m is 44.25 lbf·in.
What is a kgf·m in N·m?
Exactly 9.80665 N·m, the torque of one kilogram-force acting perpendicularly on a 1 m lever. Older workshop manuals give torque in kgf·m, sometimes written kg·m or kgm, so a 10 kgf·m figure is 98.07 N·m or 72.33 lbf·ft.
Why is torque not measured in joules?
Torque and energy are different quantities that happen to share the dimension N·m. NIST SP 811 states that the SI unit of moment of force is the newton metre rather than the joule. Energy is force times distance moved, torque is force times lever arm, and a torque of 1 N·m acting through one full turn does 2π J of work.
About this calculator
Sources
Checked against references
This calculator includes 4 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.