Torque Converter
Convert newton meters, foot pounds, inch pounds, and kgf m.
What it does
Torque conversion multiplies by fixed factors between rotational units. The newton meter anchors SI work, foot pounds anchor US fasteners and engines, inch pounds handle small bolts, and kilogram force meters cover metric shop tools.
The tool above moves between five units with newton meters as the hub. Pick both ends, enter the value, and every equivalent appears below the answer.
The default 100 ft-lb converts to 135.5818 N·m. Reversing 50 N·m gives 36.8781 ft-lb, the number most US torque wrenches actually click at.
Factors follow NIST Special Publication 811 torque tables with the same conversion appendix behind energy units. Both fix 1 ft-lb at 1.35581795 N·m from the exact pound, foot, and gravity definitions.
How to use
- Enter the torque value.
- Pick the source unit on the left and the target on the right.
- Read the converted line first.
- Scan the all units note for the rest.
- Set wrenches in the unit the spec prints.
Formula
- 1.35581795
- N·m in one ft-lb, exact by definition.
- x12
- Inch pounds per foot pound.
- hub
- Newton meters as the single middle step.
Torque shares units with energy but twists instead of spending: never add N·m of torque to joules of work. Specs mixing in-lb with ft-lb differ twelvefold.
Worked example
Example: 100 ft-lb to N·m
Value 100, from ft-lb, to N·m.
- Factor: 1.35581795 N·m per ft-lb.
- Multiply: 100 x 1.35581795 = 135.581795.
- Round to four places: 135.5818 N·m.
- Reverse: 135.5818 / 1.35581795 = 100 ft-lb back.
- Result: 100 ft-lb = 135.5818 N·m.
Reference table
| Spec | N·m | Everyday check |
|---|---|---|
| 100 in-lb | 11.2985 | Small bolt, just over 8 ft-lb |
| 20 ft-lb | 27.1164 | Spark plug zone |
| 100 ft-lb | 135.5818 | Lug nut zone |
| 150 ft-lb | 203.3727 | Heavy suspension work |
Limits
- Units only; friction and angle need procedures.
- Dry versus lubed threads change clamp.
- Stretch and angle specs need their own procedure.
- Rusty fasteners read high before they turn.
Common mistakes
- Reading in-lb specs as ft-lb (12x over torque).
- Adding torque N·m into energy joules.
- Rounding mid chain across conversions.
- Trusting uncalibrated click wrenches.
- Ignoring dry versus lubed spec conditions.
Try it yourself
Quick checks. Answers sit tucked under each question.
50 N·m in ft-lb?
50 / 1.35581795 = 36.8781 ft-lb.
12 in-lb in ft-lb?
12 / 12 = 1 ft-lb.
10 kgf·m in N·m?
10 x 9.80665 = 98.0665 N·m.
Questions
How many N·m in a ft-lb?
1.35581795 N·m, exact from pound, foot, and gravity definitions.
in-lb or ft-lb?
Twelve in-lb make one ft-lb. Small bolts print in-lb.
Torque vs energy?
Same unit dimensions, different physics: twisting versus spending.
What is kgf·m?
Metric shop unit: 9.80665 N·m each.
Why calibrate wrenches?
Springs drift; yearly checks keep clicks honest.
Dry or lubed?
Follow the spec condition: lube radically changes clamp at one torque.