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CalcChef

Torque Converter

Convert torque between N·m, lb·ft, lb·in and kgf·m. 1 N·m = 0.737562 lb·ft = 8.85075 lb·in, and 100 lb·ft = 135.582 N·m. How it works

Use the Torque Converter

Result
0.737562 lb·ft
lb·in 8.85075 · kgf·m 0.101972

1 N·m ≈ 0.737562 lb·ft

All units

Newton-meters (N·m)1
Pound-feet (lb·ft)0.737562
Pound-inches (lb·in)8.85075
Kilogram-force meters (kgf·m)0.101972

About the Torque Converter

1 N·m is 0.737562 lb·ft and 1 lb·ft is 1.35582 N·m. The converter also handles pound-inches (12 lb·in make 1 lb·ft) and kilogram-force meters (1 kgf·m is exactly 9.80665 N·m). To change lb·ft to N·m, multiply by 1.35582: 100 lb·ft is 135.582 N·m.

Pound-feet in N·m, lb·in and kgf·m

lb·ftN·mlb·inkgf·m
1013.55821201.38255
2533.89543003.45637
5067.79096006.91275
80108.46596011.0604
100135.582120013.8255
150203.373180020.7382
200271.164240027.651

Six significant digits, as the converter shows them.

Newton-meters in lb·ft, lb·in and kgf·m

N·mlb·ftlb·inkgf·m
107.3756288.50751.01972
2518.4391221.2692.54929
5036.8781442.5375.09858
10073.7562885.07510.1972
150110.6341327.6115.2957

Pound-inches in N·m and lb·ft

lb·inN·mlb·ft
101.129850.833333
202.25971.66667
505.649244.16667
10011.29858.33333

NGK spark plug torque in N·m and lb·ft

Thread and seatCast iron head (N·m)Cast iron head (lb·ft)Aluminum head (N·m)Aluminum head (lb·ft)
18 mm, flat seat (gasket)35–4525.8147–33.190335–4025.8147–29.5025
14 mm, flat seat (gasket)25–3518.4391–25.814725–3018.4391–22.1269
12 mm, flat seat (gasket)15–2511.0634–18.439115–2011.0634–14.7512
10 mm, flat seat (gasket)10–157.37562–11.063410–127.37562–8.85075
8 mm, flat seat (gasket)––8–105.9005–7.37562
18 mm, conical seat20–3014.7512–22.126920–3014.7512–22.1269
12 and 14 mm, conical seat15–2511.0634–18.439110–207.37562–14.7512

N·m ranges from NGK’s spark plug overtightening sheet (Niterra UK), for clean, dry threads; the lb·ft cells are the converter’s result for each end. NGK’s sheet prints its own lb·ft figures about 2% lower (18.0 for 25 N·m). The engine maker’s figure comes first.

How to use this tool

  1. Type the torque in the From box and pick its unit: N·m, lb·ft, lb·in or kgf·m.
  2. Pick the To unit. The result and the line “1 unit ≈ …” update as you type.
  3. Use the swap button to turn the conversion around.

Frequently asked questions

How do I convert Nm to ft lb?
Multiply newton-meters by 0.737562 to get pound-feet. 50 N·m is 36.8781 lb·ft and 100 N·m is 73.7562 lb·ft.
How do I convert ft lb to Nm?
Multiply pound-feet by 1.35582. 80 lb·ft is 108.465 N·m and 150 lb·ft is 203.373 N·m.
How many inch pounds are in a foot pound?
12. 1 lb·ft is 12 lb·in, so 10 lb·in is 0.833333 lb·ft and 1.12985 N·m.
How many N·m is 1 kgf·m?
9.80665 exactly, because a kilogram-force is a kilogram under standard gravity. 1 N·m is 0.101972 kgf·m, and 10 kgf·m is 98.0665 N·m.
Is a foot-pound the same as a pound-foot?
For torque, people use them interchangeably, but a foot-pound is properly a unit of work and a pound-foot is the torque unit. The converter’s lb·ft is the torque unit.
Is this the torque converter in a car transmission?
No. This is a unit converter for torque values. The torque converter in an automatic transmission is a fluid coupling.

When the manual and the wrench disagree

A European car manual gives its wheel nuts in N·m, while a click-type wrench bought in the US is scaled in lb·ft: a 140 N·m spec is 103.259 lb·ft, so set the wrench to 103. Bicycle and small-engine specs often come in N·m while a small 1/4 in drive wrench reads lb·in: 25 N·m is 221.269 lb·in. Some older service manuals list kgf·m, and 10 kgf·m is 72.3301 lb·ft. The factors in one line: 1 N·m = 0.737562 lb·ft = 8.85075 lb·in = 0.101972 kgf·m, and 100 lb·ft is 135.582 N·m.

Type in the From box and pick the two units; the swap button turns the pair around, and the line under the result shows what one From unit equals.

Everything goes through newton-meters

result = value × (N·m per from-unit) ÷ (N·m per to-unit)

Factors used, at full precision:

  • 1 lb·ft = 1.3558179483314004 N·m

  • 1 lb·in = 1/12 lb·ft = 0.1129848290 N·m

  • 1 kgf·m = 9.80665 N·m, exactly

Example: 100 lb·ft × 1.35582 ÷ 1 = 135.582 N·m, and the same torque is 1,200 lb·in or 13.8255 kgf·m. Results show six significant digits in plain notation, so a very large or very small value prints its digits and not an exponent.

The pound-foot factor follows from 0.45359237 kg per pound, 9.80665 m/s² and 0.3048 m per foot: the force of one pound under standard gravity acting at one foot.

Fun Fact: The name pound-foot was proposed to keep torque apart from the foot-pound, a unit of work. Wikipedia says it apparently came from the physicist Arthur Mason Worthington, yet people still often call torque units foot-pounds (ft-lb).

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