Nm to Ft-Lbs Converter (Torque)
Convert between Newton-metres (Nm) and foot-pounds (ft-lb) of torque in both directions. Common for automotive service, bicycle wrenches, and DIY assembly.
Last updated: September 2026
Compare with similar
About this calculator
Torque = force × distance. In SI units, 1 Newton × 1 metre = 1 Nm. In US customary, 1 pound-force × 1 foot = 1 ft-lb (also called lb-ft). Conversion factor: 1 ft-lb = 1.35582 Nm exactly (from the pound-force definition 4.4482 N × 12/12 ft-per-inch × 1 ft = 4.4482 × 0.3048 m = 1.35582 Nm).
Automotive service manuals in the US typically list torque values in ft-lb (or in-lb for small fasteners, where 12 in-lb = 1 ft-lb). Vehicles built for European or Asian markets list Nm. A common source of engine mistakes is confusing the two — a bolt spec'd at 30 Nm should be torqued to 22 ft-lb (30 / 1.356), not 30 ft-lb (which would be 41 Nm and could strip the threads).
Torque wrench selection matters: use a wrench whose full-scale is within about 20–80% of the target torque for best accuracy. A 250 ft-lb wrench at 30 ft-lb has a ±25% error band; a 100 ft-lb wrench at 30 ft-lb is ±5%. Click-type wrenches drift and need periodic calibration.
How to use
Example — 100 Nm to ft-lb. 100 / 1.35582 = 73.8 ft-lb. That is a typical passenger-car lug-nut torque. Use a 1/2" drive click-type torque wrench in the 20–150 ft-lb range. Example — 200 ft-lb to Nm. 200 × 1.35582 = 271.2 Nm. That is a heavy-truck axle-nut or big-block cylinder-head torque. Torque multiplier tools help reach this range without excessive arm force.
Frequently asked questions
Is ft-lb the same as lb-ft?
Yes — ft-lb and lb-ft mean the same thing (foot × pound-force = pound-force × foot, since multiplication is commutative). ASTM and SAE style guides prefer "lb·ft" or "lbf·ft" for torque and "ft-lb" for energy (foot-pounds of work), but the practical difference is nil.
What is a torque angle spec?
Modern engine fasteners often use "torque-plus-angle" — snug to a low initial torque (say 50 Nm), then turn a specified additional angle (say 90°). This yields more consistent clamping force than a pure torque spec, because it accounts for thread friction variability. Requires a degree wheel or torque-angle gauge.
Should I torque wet or dry threads?
Follow the service manual. Most factory torque specs assume clean, dry threads. Adding oil or anti-seize reduces friction; the same measured torque produces a higher preload, potentially stripping or breaking the bolt. Some specs (especially rod and main bearing bolts) explicitly require lubricated threads — check the manual.
Do impact wrenches produce torque?
Yes but not precisely. Impact drivers apply repeated hammer blows; the effective torque depends on air pressure, duty cycle, and material springback. Impact-tightened fasteners should be finished with a calibrated torque wrench, especially for wheels, brakes, and structural fasteners. Never trust "run to airgun feel".