Ft-Lbs to Nm Converter
Convert foot-pounds (lb-ft) to newton-meters (N·m) for wrenches and specs
1 foot-pound = 1.355818 newton-meters. To convert ft-lbs to Nm, multiply by 1.355818, so 80 ft-lbs is 108.47 N·m.
How to convert ft-lbs to Nm
Torque is force times lever length, so the conversion is just the force conversion multiplied by the length conversion. One pound-force is 4.448222 newtons and one foot is exactly 0.3048 meters. Multiply them and one foot-pound is 1.3558179483 N·m, a factor that follows exactly from the definitions of the pound, the foot and standard gravity. Multiplying a ft-lb value by it gives newton-meters. The Nm to ft-lbs converter divides by the same factor, and the torque converter covers in-lbs, kgf·m and kgf·cm too.
A useful sanity check is that the N·m number should always be about a third bigger than the ft-lb number. If 60 ft-lbs comes out as 44, you divided when you should have multiplied; the correct answer is 81.35 N·m. For the force part alone, the pounds to newtons converter shows the same 4.448 factor at work.
Step by step
- Take the torque in foot-pounds (ft-lbs or lb-ft).
- Multiply it by 1.3558179483.
- Round to your wrench's graduation, usually the nearest whole N·m.
See it on a scale
Worked examples
An 18 ft-lb spark plug, an 80 ft-lb lug nut and a 300 lb-ft engine rating, the kind of figures found in US service manuals and brochures.
18 lbf·ft ÷ 0.7375621493 = 24.404723 N·m
= 24.404723 N·m
80 lbf·ft ÷ 0.7375621493 = 108.46544 N·m
= 108.46544 N·m
300 lbf·ft ÷ 0.7375621493 = 406.74538 N·m
= 406.74538 N·m
How do I convert ft-lbs to Nm in Excel or Google Sheets?
Put the foot-pounds in A2 and use =A2*1.3558179483; the result is newton-meters, exact to ten significant figures.
A wrench can only be set to its graduations, so add a rounded column for the tool: =ROUND(A2*1.3558179483,0) turns 80 ft-lbs into 108 N·m. Keep the unrounded column for your records. A few companion formulas cover the rest of a typical service sheet:
- Inch-pounds to N·m:
=A2*0.112984829 - N·m back to ft-lbs:
=A2/1.3558179483 - kgf·m to ft-lbs:
=A2*7.233014 - Torque plus angle: convert only the torque cell and copy the angle column unchanged
For a whole manual, list each fastener with its original unit in column B, then convert with =IF(B2="ft-lb",A2*1.3558179483,A2) so that specs already in N·m pass through untouched. The same formulas work unchanged in Google Sheets. Before printing, sort the sheet by fastener rather than by value, so it reads in the same order as the service procedure.
How much torque is 1 foot-pound?
One foot-pound is the twist produced by one pound-force pushing at right angles on the end of a one-foot lever, which equals 1.3558 N·m. Hanging a 1 lb weight from the end of a 12-inch wrench held level produces it.
Because torque is force times distance, the same 1 ft-lb can be made many ways: 2 lbf at 6 inches, or 0.5 lbf at 24 inches. That is also why a longer wrench makes a tight bolt easier to turn, since the same hand force produces more torque. In metric terms, one foot-pound matches a 1 kg mass hanging from a lever 13.83 cm long at standard gravity; the foot itself is exactly 0.3048 m, as the feet to meters converter shows.
Hand effort puts larger specs in context: an 80 ft-lb spec on an 18-inch breaker bar needs about 53.3 lbf of push at the handle, roughly the weight of a 24.2 kg mass.
Why do European and Asian manuals give torque in Nm?
Because the newton-meter is the SI unit of torque, and manufacturers outside the US write service data in SI units, as ISO standards and the BIPM SI Brochure do.
The United States is the main market still using foot-pounds and inch-pounds for service work, so global manufacturers often print both. Where only one unit appears, it is usually N·m, and older Japanese documents may add a kgf·m figure in brackets. When two figures are printed side by side, they were converted from each other and differ only by rounding, so either is fine with a matching wrench.
ISO 6789, the international standard for hand torque tools, is written in newton-meters too, and wrenches sold worldwide commonly carry an N·m scale. If a European manual meets a wrench marked only in ft-lbs, divide the N·m value by 1.3558 instead of multiplying.
Ft-lbs to Nm conversion chart
Foot-pounds converted to newton-meters and rounded to two decimal places. The low rows cover small engine bolts; the high rows cover wheels, suspension and engine output.
| Pound-feet (lbf·ft) | Newton-meters (N·m) |
|---|---|
| 1 lbf·ft | 1.36 N·m |
| 2 lbf·ft | 2.71 N·m |
| 3 lbf·ft | 4.07 N·m |
| 4 lbf·ft | 5.42 N·m |
| 5 lbf·ft | 6.78 N·m |
| 6 lbf·ft | 8.13 N·m |
| 7 lbf·ft | 9.49 N·m |
| 8 lbf·ft | 10.85 N·m |
| 9 lbf·ft | 12.2 N·m |
| 10 lbf·ft | 13.56 N·m |
| 12 lbf·ft | 16.27 N·m |
| 15 lbf·ft | 20.34 N·m |
| 18 lbf·ft | 24.4 N·m |
| 20 lbf·ft | 27.12 N·m |
| 25 lbf·ft | 33.9 N·m |
| 30 lbf·ft | 40.67 N·m |
| 35 lbf·ft | 47.45 N·m |
| 40 lbf·ft | 54.23 N·m |
| 45 lbf·ft | 61.01 N·m |
| 50 lbf·ft | 67.79 N·m |
| 60 lbf·ft | 81.35 N·m |
| 70 lbf·ft | 94.91 N·m |
| 75 lbf·ft | 101.69 N·m |
| 80 lbf·ft | 108.47 N·m |
| 90 lbf·ft | 122.02 N·m |
| 100 lbf·ft | 135.58 N·m |
| 110 lbf·ft | 149.14 N·m |
| 120 lbf·ft | 162.7 N·m |
| 130 lbf·ft | 176.26 N·m |
| 140 lbf·ft | 189.81 N·m |
| 150 lbf·ft | 203.37 N·m |
| 175 lbf·ft | 237.27 N·m |
| 200 lbf·ft | 271.16 N·m |
| 250 lbf·ft | 338.95 N·m |
| 300 lbf·ft | 406.75 N·m |
| 400 lbf·ft | 542.33 N·m |
| 500 lbf·ft | 677.91 N·m |
Foot-pounds vs newton-meters: what is the difference?
Both measure torque, a force acting at a distance from a pivot; the foot-pound combines US customary force and length units, and the newton-meter combines SI ones.
| Attribute | Pound-feet | Newton-meters |
|---|---|---|
| Symbol | lbf·ft | N·m |
| System | Imperial / US | SI |
| Defined as | 1.3558179483 N·m | 1 N × 1 m |
| One unit equals | 1.3558179 N·m | 0.73756215 lbf·ft |
| Built from | 1 lbf acting on a 1 ft lever | 1 N acting on a 1 m lever |
| Also written | lb-ft, lbf·ft, ft-lb, ft·lbf | Nm, N·m, N m |
| Documented in | NIST SP 811, via the 1959 pound and foot | BIPM SI Brochure |
| Where it is used | US service manuals, US engine ratings and US-market torque wrenches | European and Asian manuals, bicycle parts and ISO standards |
| Smaller unit for small fasteners | Inch-pound (1/12 ft-lb) | N·cm (1/100 N·m) on torque screwdrivers |
4 key differences
- A foot-pound is 1.356 times a newton-meter, so a spec written in N·m is always a number roughly 36% larger.
- The foot-pound is defined through standard gravity, via the pound-force, while the newton-meter needs no gravity at all.
- US usage writes energy and torque with the same words, ft-lb and lb-ft, while the SI separates them into joules for energy and newton-meters for torque.
- An inch-pound divides the foot-pound exactly by 12, whereas the newton-meter's smaller units step by powers of ten, such as N·cm and N·mm.
Common US torque specs in newton-meters
Typical ranges from US manuals, converted to N·m and rounded. They show what a normal figure looks like, but the correct value depends on the exact vehicle, fastener and thread condition, so always follow the manufacturer's specification.
| Fastener | Typical range (ft-lbs) | Typical range (N·m) |
|---|---|---|
| Passenger car lug nuts | 76–100 ft-lbs | 103–136 N·m |
| Half-ton pickup lug nuts | 120–165 ft-lbs | 163–224 N·m |
| Heavy truck wheel nuts (hub-piloted) | 450–500 ft-lbs | 610–678 N·m |
| Spark plug, 14 mm gasket seat, aluminum head | 18–22 ft-lbs | 24–30 N·m |
| Engine oil drain plug | 15–30 ft-lbs | 20–41 N·m |
What are torque-plus-angle and torque-to-yield bolts?
Torque-plus-angle bolts are tightened to a set torque and then turned through a further angle, and torque-to-yield (TTY) bolts are the ones designed to stretch permanently during that final turn, so they are usually single-use.
Cylinder heads, main bearings and many suspension bolts are now tightened to a torque and then turned a further angle, written as something like “30 ft-lbs + 90°”. Only the torque part needs converting. That spec becomes 40.7 N·m + 90°; the angle stays exactly the same because degrees are not tied to a unit system. Use an angle gauge for the second step rather than guessing a quarter turn.
Many of these are torque-to-yield (TTY) bolts that stretch permanently when tightened. Manufacturers usually require new ones every time, whatever unit the spec is written in. If you want the angle in other units, the degrees to radians converter is there, though no manual asks for it.
How precise does the conversion need to be?
Rounding to the nearest whole newton-meter is precise enough, because the ISO 6789 standard for hand torque tools allows common click-type wrenches a tolerance of about ±4% of the reading, and some types ±6%. On an 80 ft-lb setting, ±4% is roughly ±3 ft-lbs, or about ±4 N·m.
Converting 80 ft-lbs gives 108.47 N·m. Setting 108 N·m on a metric wrench introduces an error of only 0.43%, far inside the tool's own tolerance. Rounding to the nearest whole N·m is therefore the right level of precision. What matters much more is converting from the original spec, keeping threads clean and pulling the wrench smoothly.
Engine torque in lb-ft and Nm, with the power it makes
Power depends on torque and engine speed: hp = lb-ft × rpm ÷ 5,252. This table converts common torque ratings to N·m and shows the horsepower each would produce at 3,000 and 6,000 rpm. To switch power units, use the hp to kW converter.
| Torque (lb-ft) | Torque (N·m) | Power at 3,000 rpm | Power at 6,000 rpm |
|---|---|---|---|
| 100 lb-ft | 135.6 N·m | 57 hp | 114 hp |
| 150 lb-ft | 203.4 N·m | 86 hp | 171 hp |
| 200 lb-ft | 271.2 N·m | 114 hp | 228 hp |
| 300 lb-ft | 406.7 N·m | 171 hp | 343 hp |
| 400 lb-ft | 542.3 N·m | 228 hp | 457 hp |
| 500 lb-ft | 677.9 N·m | 286 hp | 571 hp |
When do you need to convert ft-lbs to Nm?
You need it whenever a US spec in foot-pounds meets something metric: an N·m-only torque wrench, an international spec sheet or an SI engineering document.
- You own a metric-only wrench. Many European and Asian torque wrenches and digital adapters read only N·m, while US manuals print ft-lbs.
- You are comparing engines. International reviews, spec sheets and racing regulations quote torque in N·m.
- You are writing technical documents. Engineering reports and ISO-based documents use the SI unit, N·m.
- You are working on small fasteners. Low specs are often given in inch-pounds; divide by 12 to get ft-lbs first, or use the Nm to in-lbs converter to check the result.
Sources and further reading
The standards and references behind the numbers on this page. Links open in a new tab.
Standards and official sources
Further reading
- Pound-footWikipedia
- Newton-meterWikipedia
Ft-lbs to Nm FAQs
Short, exact answers to what people ask most.
What is 80 ft-lbs in Nm?
80 ft-lbs equals 108.47 N·m, so you would set about 108 N·m. It is a common lug-nut torque for small and midsize cars.
How many Nm is 1 ft-lb?
One foot-pound is 1.3558179483 N·m, usually rounded to 1.356. It follows from 1 lbf = 4.4482 N and 1 ft = 0.3048 m.
What is 100 ft-lbs in Nm?
100 ft-lbs is 135.58 N·m. Multiply any ft-lb value by 1.3558179483 to get newton-meters.
What is 150 ft-lbs in Nm?
150 ft-lbs equals 203.37 N·m, about 203 N·m. Figures like this are typical for pickup truck lug nuts and suspension bolts.
How do I convert ft-lbs to Nm quickly?
Multiply by 1.36, or add about a third. For example, 40 ft-lbs × 1.36 = 54.4 N·m, against an exact 54.23 N·m.
Do I convert the angle in a torque-plus-angle spec?
No. Only the torque changes. A spec of 30 ft-lbs + 90° becomes 40.7 N·m + 90°, because the angle is the same in every unit system.
What is 25 ft-lbs in Nm?
25 ft-lbs equals 33.9 N·m, so set about 34 N·m on a metric wrench.
What is 30 ft-lbs in Nm?
30 ft-lbs is 40.67 N·m, which rounds to 41 N·m.
What is 50 ft-lbs in Nm?
50 ft-lbs equals 67.79 N·m, about 68 N·m.
What is 120 ft-lbs in Nm?
120 ft-lbs is 162.7 N·m. That falls in the typical lug-nut range for half-ton pickups, but confirm the figure in your owner's manual.
How many Nm is 250 lb-ft of engine torque?
250 lb-ft equals 338.95 N·m, which a European brochure would round to 339 N·m.
Related conversions
Conversion factors from NIST SP 811 (2008), Appendix B, and the 1959 International Yard and Pound Agreement; the newton-meter as the SI unit of torque from the BIPM SI Brochure (9th ed.); torque tool tolerances from ISO 6789-1; typical specs are common manufacturer ranges, not a replacement for your service data. Last updated . How we verify our numbers.