# Pound-feet to newton-meters converter

> Convert pound-feet to newton-meters (ft-lbs to Nm) with the exact factor, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/foot-pounds-to-newton-meters
Subject: Unit converters

A pound-foot torque specification can be restated for a metric torque wrench. Check that the source says pound-feet rather than pound-inches, which differ by a factor of twelve. Retain any tightening sequence or conditions supplied with the original specification.

One pound-foot is about 1.3558179483 newton-meters, so 80 lbf·ft is 108.465436 N·m. To convert ft-lbs to Nm, multiply by 1.3558179483; to convert back, multiply by 0.7375621493.

One pound-foot is one pound-force (4.4482216152605 N) acting at one foot (0.3048 m), exactly 1.3558179483314004 N·m. The factor has no exact decimal form, so results are computed with 50 significant digits and rounded only for display.

## Inputs

- **Pound-feet (lbf·ft)**

## Results

- Newton-meters (N·m) — main result
- Conversion
- 1 N·m in pound-feet (lbf·ft)

## Formula

$$
\text{newton-meters} = \text{pound-feet} \times 1.35581794833
$$

## Worked examples

### 80 lbf·ft to N·m

- Pound-feet (lbf·ft): 80 lbf·ft
- **Newton-meters: 108.465435867 N·m**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 25 lbf·ft to N·m

- Pound-feet (lbf·ft): 25 lbf·ft
- **Newton-meters: 33.8954487083 N·m**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 200 lbf·ft to N·m

- Pound-feet (lbf·ft): 200 lbf·ft
- **Newton-meters: 271.163589666 N·m**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### When would I convert ft-lbs to Nm?

A pound-foot torque specification can be restated for a metric torque wrench. Check that the source says pound-feet rather than pound-inches, which differ by a factor of twelve. Retain any tightening sequence or conditions supplied with the original specification.

### How many newton-meters are in a pound-foot?

One pound-foot is about 1.3558179483 newton-meters. One pound-foot is one pound-force (4.4482216152605 N) acting at one foot (0.3048 m), exactly 1.3558179483314004 N·m.

### How do you convert ft-lbs to Nm?

Multiply the number of pound-feet by 1.3558179483. For example, 80 lbf·ft × 1.3558179483 = 108.465436 N·m. To go the other way, divide by 1.3558179483.

### How can I estimate ft-lbs to Nm without a calculator?

Multiply by 1.36. That is 0.3% high of the exact factor 1.3558179483, so 80 lbf·ft comes out as 108.8 N·m instead of 108.4654.

### How accurate is the pound-feet to newton-meters converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “80 lbf·ft to N·m” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)