Torque units: ft-lb, N·m, in-lb and kgf·m

Torque is a force times the distance it acts from the center of the bolt. A foot-pound (ft-lb) is one pound of force on a one-foot lever, 1.356 N·m; a newton-meter (N·m) is one newton on a one-meter lever. An inch-pound is a twelfth of a foot-pound, and a kilogram-force meter (kgf·m) is 9.807 N·m.

Sources checked

What each unit is

Torque is a turning force: a force times the distance from where it acts to the center of the bolt. So every torque unit is a force unit times a length unit, and the same torque can come from a small force on a long handle or a big one on a short handle.

UnitOne of them isIn N·m
Foot-pound (ft-lb, lb-ft, lbf·ft)One pound of force on a one-foot lever1.355818
Inch-pound (in-lb, lbf·in)One pound of force on a one-inch lever: a twelfth of a foot-pound0.112985
Newton-meter (N·m)One newton of force on a one-meter lever, the SI unit1
Kilogram-force meter (kgf·m)The weight of one kilogram, at standard gravity, on a one-meter lever9.80665

A pound-force is the weight of one pound at standard gravity: 0.45359237 kg × 9.80665 m/s², 4.4482 N. With the foot at exactly 0.3048 m, that makes the factors exact; NIST lists the same ones rounded to seven digits.

Converting between them

Read across: one of the unit on the left is this many of the unit at the top.

1 offt-lbN·min-lbkgf·m
ft-lb11.35582120.138255
N·m0.73756218.850750.101972
in-lb0.08333330.11298510.0115212
kgf·m7.233019.8066586.79621

For a quick sum: ft-lb × 1.356 = N·m, N·m × 0.738 = ft-lb, ft-lb × 12 = in-lb, and kgf·m × 9.807 = N·m. For any other value, type it into the torque converter.

Which units car manuals print

Of the 3,995 owner’s manual pages on this site, almost all print the wheel torque in both lb-ft and N·m. Kilogram-force meters appear only in the manuals of Acura, Genesis, Honda, Hyundai, Infiniti, Kia, Lexus, Mazda, Subaru and Toyota, usually as a third unit beside the other two. A few print no lb-ft: Rivian’s owner’s guides give N·m only, as do 3 Lucid manuals, 8 Mercedes-Benz manuals and 48 Porsche manuals, and 9 Hyundai manuals give kgf·m with or without N·m. There the site works the missing units out and labels them converted.

MakePageslb-ftN·mkgf·m
Acura143143143142
Alfa Romeo999–
Buick929292–
Cadillac139139139–
Chevrolet331331331–
Chrysler494949–
Dodge989898–
Fiat343434–
Ford378378378–
Genesis44444444
GMC142142142–
Honda299299299293
Hyundai190181172189
Infiniti1011011013
Jeep108108108–
Kia125125125125
Lexus11111111
Lincoln127127127–
Lucid303–
Mazda123123123112
Mercedes-Benz563555563–
Mitsubishi383838–
Nissan252252252–
Polestar101010–
Porsche279231249–
Ram595959–
Rivian505–
Subaru25252525
Tesla555–
Toyota14141414
Volvo199199199–

Manual pages that print each unit. One printed wrongly, such as Hyundai’s “07~127” for 107~127 N·m, isn’t counted.

The pound-foot alone is spelled 33 ways in those pages. The commonest are “lb ft” (654), “lb-ft” (649), “ft-lb” (569), “lbf·ft” (463), “ftlb” (184) and “lb.ft” (182), and the rarer ones include “lb·ft”, “ft/lb.” and “ft-lb.”. They all mean the same thing.

When the two numbers don’t match

A manual rounds each unit on its own, so the pair it prints is rarely an exact conversion. Usually the gap is a fraction of a unit; GM’s manuals round hardest. These are the pairs printed most often:

PrintedPagesMakesPrinted N·m in lb-ft
140 lb-ft, 190 N·m424Acura, Buick, Cadillac, Chevrolet, Ford, GMC, Honda140.1
100 lb-ft, 135 N·m380Chrysler, Dodge, Ford, Jeep, Lincoln, Mazda99.6
80 lb-ft, 108 N·m318Acura, Honda79.7
111 lb-ft, 150 N·m305Dodge, Mercedes-Benz110.6
100 lb-ft, 140 N·m245Buick, Cadillac, Chevrolet, GMC103.3 (3.3% apart)
118 lb-ft, 160 N·m237Porsche, Volvo118.0

Ranges carry the same rounding. Kia, Hyundai and Genesis print 11–13 kgf·m as 79–94 lb-ft and 107–127 N·m: 11 kgf·m is 79.6 lb-ft and 107.9 N·m, and 13 kgf·m is 94.0 lb-ft and 127.5 N·m.

So set the wrench to the number the manual prints in the unit the wrench reads, rather than converting the other one. Where the manual gives only one unit, convert it exactly and round to the nearest step your wrench can be set to.

Where inch-pounds come in

Inch-pounds keep small torques in whole numbers. This site gives 1/4" bolts in in-lb: a 1/4-20 Grade 5 bolt takes 101 in-lb dry, which is 8.4 ft-lb (see the 1/4" bolt page). A wrench marked in N·m covers the same work: 2 to 20 N·m is 18 to 177 in-lb.

Before setting a small wrench, check which unit the spec is in: 20 in-lb and 20 ft-lb differ twelvefold. The torque wrench guide covers setting and using one.

Questions

How do I convert ft-lb to N·m?

Multiply by 1.3558: 100 ft-lb is 135.6 N·m. To go back, multiply N·m by 0.7376, or use the torque converter.

Is ft-lb the same as lb-ft?

For torque, yes: both are a pound of force on a one-foot lever, and the number is the same. NIST’s conversion table writes the torque unit as lbf·ft and keeps ft·lbf for energy (work), but the manuals on this site use both for torque.

Is a newton-meter the same as a joule?

No. In NIST’s conversion table the pound-foot of torque (lbf·ft) converts to newton-meters, while the foot-pound of energy (ft·lbf) converts to joules, both by 1.355818. Torque is given in N·m.

Why don’t the N·m and lb-ft in my manual match exactly?

Each is rounded on its own, and some manuals round harder than others. GM’s print 140 N·m next to 100 lb-ft, though 140 N·m is 103.3 lb-ft. Set your wrench to the number printed in the unit it reads.

Sources

  1. NIST: Guide to the SI (SP 811), Appendix B.8: conversion factors for units listed alphabetically (checked October 23, 2026)

Spotted a number that doesn’t match your manual or a source? Tell us; corrections are logged on the sources page.

The units and values quoted from owner’s manuals link from each vehicle’s page in lug nut torque by vehicle.