Newton-Meters to Foot-Pounds Converter
Convert N·m to ft-lb (lb-ft) and back for wheel nuts, engine and suspension torque specs and car spec sheets, with inch-pounds and kgf·m shown alongside.
1 N·m = 0.737562 ft-lb · 1 ft-lb = 1.355818 N·m
N·m to ft-lb Formula
A foot-pound is one pound-force (exactly 4.4482216152605 N) acting at one foot (exactly 0.3048 m), so 1 ft-lb = 1.3558179 N·m and the factor is exact. For a quick check in the garage, N·m × ¾ is close: it overstates by about 1.7%, so 100 N·m comes out as 75 ft-lb rather than 73.8. Use the exact figure when you actually set a wrench.
N·m to ft-lb Table for Workshop Torque Specs
The range of a typical ½ in drive click wrench, which covers most wheel, suspension and brake fasteners.
| N·m | ft-lb | in-lb |
|---|---|---|
| 20 N·m | 14.8 | 177 |
| 30 N·m | 22.1 | 266 |
| 40 N·m | 29.5 | 354 |
| 50 N·m | 36.9 | 443 |
| 60 N·m | 44.3 | 531 |
| 80 N·m | 59 | 708 |
| 100 N·m | 73.8 | 885 |
| 110 N·m | 81.1 | 974 |
| 120 N·m | 88.5 | 1,062 |
| 130 N·m | 95.9 | 1,151 |
| 140 N·m | 103.3 | 1,239 |
| 150 N·m | 110.6 | 1,328 |
| 180 N·m | 132.8 | 1,593 |
| 200 N·m | 147.5 | 1,770 |
| 250 N·m | 184.4 | 2,213 |
| 300 N·m | 221.3 | 2,655 |
Worked Example: 120 N·m Wheel Nuts
The owner's manual gives the wheel nut (lug nut) torque as 120 N·m, and your click wrench is marked in foot-pounds.
Step 1: Multiply by the factor
Step 2: Round to the wrench scale
Set the wrench to about 88.5 ft-lb. Tighten the nuts in a star (criss-cross) pattern so the wheel seats evenly, and check them again after a short drive, as tyre fitters advise. Car wheel nut specs typically fall somewhere between 80 and 140 N·m (59–103 ft-lb), but always use the figure for your vehicle. An impact gun on its own is not a substitute for a torque wrench.
Engine Torque: N·m vs lb-ft on Spec Sheets
European and Asian brochures quote an engine's peak torque in N·m. US brochures and reviews use lb-ft, which is the same unit as ft-lb written in a different order. To compare two cars, convert one figure:
| Peak torque (N·m) | lb-ft |
|---|---|
| 150 N·m | 111 |
| 200 N·m | 148 |
| 250 N·m | 184 |
| 300 N·m | 221 |
| 350 N·m | 258 |
| 400 N·m | 295 |
| 500 N·m | 369 |
| 600 N·m | 443 |
| 800 N·m | 590 |
| 1,000 N·m | 738 |
Peak torque is quoted at a particular engine speed (for example 350 N·m at 1,500–4,000 rpm). The conversion changes only the unit, not the rpm range.
kgf·m in Older Service Manuals
Older Japanese and European workshop manuals often list torque in kgf·m (sometimes printed as kg-m or m-kg), the weight of 1 kg acting at 1 metre. 1 kgf·m is exactly 9.80665 N·m, or 7.233 ft-lb. A manual that says "wheel nuts 9–11 kg-m" means 88–108 N·m, or 65–80 ft-lb. The converter shows kgf·m under every result, so you can check a manual that mixes units.
Torque-Plus-Angle Specs
Cylinder head bolts, crank bolts and many suspension bolts use a two-stage spec such as "40 N·m + 90°". Only the torque part is converted (40 N·m = 29.5 ft-lb). The angle stays the same in any unit system, and you measure it with an angle gauge, not the torque wrench. Many such bolts are torque-to-yield and are meant to be replaced rather than reused, so follow the manual on that too.
N·m, Joules and Foot-Pounds of Energy
A newton-metre of torque has the same base units as a joule of energy, and the foot-pound is used for both too. The physics is different: torque is a turning force at a distance, while energy is a force acting through a distance. That is why SI writes torque as N·m and keeps J for energy. Numerically the factor is the same either way (1 J = 0.7376 ft-lbf of energy). But a figure like a rifle's muzzle energy in ft-lb is energy, not a torque spec, so use the energy converter for those.
Frequently asked questions
What is 100 N·m in ft-lb?
73.76 ft-lb. A quick mental check is three-quarters of the N·m figure (75), which is about 1.7% high.
Is a newton-metre bigger than a foot-pound?
No. A foot-pound is about 1.36 N·m, so the ft-lb number is always smaller than the N·m number for the same torque.
What wrench do I need for specs above 100 N·m?
A ½ in drive click wrench, which usually covers about 20–150 ft-lb (27–200 N·m). Most ⅜ in drive wrenches stop around 75–80 ft-lb.
How do I convert kg-m from a service manual to ft-lb?
Multiply by 7.233. For example, 10 kg-m is 72.3 ft-lb, or 98.1 N·m.
Sources
- NIST Special Publication 811: exact pound-force, foot and kilogram-force definitions and the ft·lbf to N·m factor.
- BIPM: The International System of Units (SI Brochure): why torque is written N·m rather than J.
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