Torque Converter
Convert torque between newton meters, foot-pounds, inch-pounds, kilogram-force meters and centimeters, and ounce-force inches. Add a wrench length to see the force you need, and check typical bolt torques.
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Distance from the bolt center to where you push.
How to use the Torque Converter
- Enter the torque value from your manual or wrench.
- Choose From and To; every other unit is listed in the results.
- Add your wrench length (optional) to see how hard you need to push.
- Scroll to the bolt tables for typical torques by size and grade.
- Copy the results or download any table as CSV.
Torque conversion factors
Torque is force multiplied by the perpendicular distance from the pivot. Each unit is just a different force unit times a different length unit, so conversions use fixed factors. The converter turns your value into newton meters first.
| Unit | In N·m | In ft·lb | In in·lb |
|---|---|---|---|
| 1 N·m | 1 | 0.737562 | 8.850746 |
| 1 ft·lb (lbf·ft) | 1.355818 | 1 | 12 |
| 1 in·lb (lbf·in) | 0.112985 | 0.083333 | 1 |
| 1 ozf·in | 0.007062 | 0.005208 | 0.0625 |
| 1 kgf·m | 9.80665 | 7.233014 | 86.79617 |
| 1 kgf·cm | 0.0980665 | 0.072330 | 0.867962 |
| 1 N·cm | 0.01 | 0.007376 | 0.088507 |
Mental shortcuts: N·m ≈ ft·lb × 1.36, ft·lb ≈ N·m × 0.74, and in·lb = ft·lb × 12.
How the bolt torque estimates are calculated
- Tensile stress area: UNC
A = 0.7854 × (D − 0.9743 ÷ n)²(n = threads per inch); metricA = 0.7854 × (d − 0.9382 × P)²(P = pitch). - Clamp load = 75% of proof load = 0.75 × proof stress × A. Proof stress: SAE Grade 5 85,000 psi, Grade 8 120,000 psi (¼–1 in); ISO class 8.8 580 MPa up to M16 and 600 MPa above, class 10.9 830 MPa.
- Torque
T = K × D × Fwith K = 0.20 for clean, dry steel and 0.15 for lubricated threads.
Example: ½-13 Grade 5: A = 0.1419 in², F = 0.75 × 85,000 × 0.1419 ≈ 9,050 lbf, T = 0.20 × 0.5 in × 9,050 ≈ 905 in·lb ≈ 75 ft·lb (102 N·m) dry.
Torque wrench tips
- Use a wrench whose range puts your target in the middle of the scale; click-type wrenches are least accurate at the very bottom of their range.
- Pull smoothly at the handle grip, at a right angle to the handle. Extensions or crow's-foot adapters that lengthen the lever change the applied torque.
- Lubricant, anti-seize or thread locker lowers friction: the same torque then produces more clamp force, so use the spec for the condition you are assembling.
- Wheel lug nuts are usually tightened in a star pattern in two or more passes.
Frequently asked questions
How do I convert ft·lb to N·m?
Multiply foot-pounds by 1.355818. For example 100 ft·lb × 1.355818 = 135.58 N·m. To convert N·m to ft·lb, multiply by 0.737562 (or divide by 1.355818).
How many inch-pounds are in a foot-pound?
Exactly 12, because a foot is 12 inches. 120 in·lb = 10 ft·lb. Small fasteners are often specified in inch-pounds, so check the unit on your torque wrench before setting it.
Are foot-pounds of torque the same as foot-pounds of energy?
They have the same units but are different quantities. Torque is a turning force (force × lever distance), and work or energy is force × distance moved along the force. To avoid confusion, torque is often written lbf·ft or pound-feet.
What is kgf·m?
A kilogram-force meter is the torque of a 1 kg weight acting on a 1 m lever under standard gravity: exactly 9.80665 N·m, or about 7.233 ft·lb. Older Japanese and European workshop manuals often use kgf·m or kgf·cm.
How do I work out the force needed on a wrench?
Divide the torque by the lever length: F = T ÷ r. To reach 100 ft·lb with an 18 in (1.5 ft) wrench you push about 100 ÷ 1.5 = 66.7 lbf at the end of the handle, at a right angle to it.
How accurate are the bolt torque tables?
They are estimates from the common short-form equation T = K × D × F, with a nut factor K of 0.20 dry or 0.15 lubricated and a clamp load of 75% of proof load. Real torque depends on thread finish, plating and lubricant, so always follow the manufacturer's specification when there is one.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.