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Calculator Answers

Torque Converter

Source: NIST Special Publication 811, Appendix B and footnotes · Source verified August 15, 2026

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

A torque converter restates a twisting force in a different unit. Torque is a force applied at a distance from an axis, so every torque unit pairs a force unit with a length unit: the newton metre pairs the newton with the metre, the pound-foot pairs the pound-force with the foot. Because the foot and the pound-force both have exact definitions in SI units, the conversion between them is exact rather than measured. Torque shares its dimensions with energy but is not the same quantity, which is why it is written in newton metres and never in joules.

Pick a unit to convert from and a unit to convert to, type a torque figure, and every common torque unit updates at once. Built for reading a service manual in one system and setting a wrench in the other: newton metres to ft lbs, ft lbs back to Nm, and the small-fastener units in between.

See also: Newtons to Pounds, Energy Converter, and Power Converter.

Quick Answer

1 N·m = 0.737562149277 lb·ft and 1 lb·ft = 1.355817948331 N·m, so 100 N·m is 73.76 lb·ft. Pick a from unit and a to unit and every other torque unit updates with it.

Decimals are fine, and so are negative values: the sign says which way it turns. · e.g. 100

Every pair goes through the newton metre, so no two units are related by a shortcut factor of their own and all six stay consistent with one another.

Torque

N·m to lb·ft

73.7562 lb·ft

100 N·m = 73.7562 lb·ft

Newton metre (N·m)100
Kilonewton metre (kN·m)0.1
Pound-foot (lb·ft)73.7562
Pound-inch (lb·in)885.0746
Ounce-inch (oz·in)14,161.1933
Kilogram-force metre (kgf·m)10.1972

1 N·m = 0.737562149277 lb·ft, and 1 lb·ft = 1.355817948331 N·m. Reach for lb·in or oz·in on small fasteners and electronics, and N·m or lb·ft for automotive and structural work.

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Examples

100 N·m

= 73.7562 lb·ft; 885.0746 lb·in

1 N·m

= 0.737562 lb·ft

50 lb·ft

= 67.7909 N·m; 600 lb·in

1 kgf·m

= 9.8067 N·m; 7.233 lb·ft

How it works

Formula · lb·ft = N·m × 0.737562149277; N·m = lb·ft × 1.355817948331

Each unit is defined by how many newton metres it is worth. The converter multiplies your figure by the source unit's value, which puts it in newton metres, then divides by the target unit's value. Everything goes through the same base, so no pair of units can drift out of step with the rest.

Newton metres to pound-feet

lb·ft = N·m × 0.737562149277

Pound-feet to newton metres

N·m = lb·ft × 1.355817948331

The two factors are reciprocals, so converting one way and back returns the number you started with.

The factor is defined rather than measured. A foot is exactly 0.3048 metres and a pound-force is exactly 4.4482216152605 newtons, so a pound-foot is exactly 1.3558179483314004 newton metres. The other units follow from the same two definitions: an inch is a twelfth of a foot and an ounce-force is a sixteenth of a pound-force, and a kilogram-force metre is standard gravity, 9.80665 N, acting through one metre.

Why every torque unit pairs a force with a length

Torque is a force applied at a distance from an axis. Push at the end of a spanner and the same push produces more twist than it would halfway along, because the distance is part of the quantity. That is why no torque unit is a single word: every one of them names a force and a length together.

pivotFrtorque = F × r

The diagram shows a straight lever arm pivoting about a point at its left end. A dimension line beneath the arm marks the distance r from the pivot to the far end. At that far end, an arrow labelled F points straight down, at right angles to the arm, and a curved arrow at the pivot shows the arm turning in response. The torque is the force F multiplied by the distance r, so one newton acting at one metre from the pivot is one newton metre, and one pound-force acting at one foot is one pound-foot.

F
Force, at right angles to the arm
r
Distance from the pivot
1 N at 1 m = 1 N·m
1 lbf at 1 ft = 1 lb·ft

Working it out by hand: 100 Nm to ft lbs

  • start with 100 N·m
  • × 0.737562149277 lb·ft per N·m
  • = 73.7562 lb·ft

Rounding the wrench setting up to a whole 74 lb·ft would put you at 100.3305 N·m instead, which is inside the tolerance of most fastener specs but worth knowing about when the spec is tight.

The other direction

Multiply by the other factor rather than dividing by the first one. Starting from 50 lb·ft: 50 × 1.355817948331 = 67.7909 N·m. A 25 lb·ft spec comes out at 33.8954 N·m the same way. Dividing 50 by 0.737562149277 gives the same answer, because the two factors are reciprocals; multiplying is just easier to check.

Down to the small-fastener units

A foot is twelve inches and an ounce-force is a sixteenth of a pound-force, so those two steps are whole numbers with nothing to round. The same 100 N·m is 885.0746 lb·in and 14,161.1933 oz·in, and 1 lb·ft is exactly 12 lb·in, which is exactly 192 oz·in.

Torque and energy are not the same quantity

Multiply a force by a distance and you get kg m²/s² either way, so torque and energy come out with identical dimensions. They are still different things. Energy is force acting along a distance and it is spent; torque is force acting at a distance from an axis, and a bolt held at 100 N·m by a wrench that is not moving is transferring no energy at all. That is why the convention keeps them apart: torque is written in newton metres and energy in joules, and nobody says a bolt is torqued to 50 joules.

The practical consequence is that this converter will not offer you joules, and that is deliberate rather than an omission. Converting a torque into an energy unit would produce a number that is arithmetically defensible and physically meaningless. If you actually want energy rather than torque, the energy converter handles joules, calories, watt-hours and BTU.

Edge cases

  • The factor is exact; the display is not. Nothing here is measured, so there is no experimental uncertainty to carry. What you see is rounded on the way to the screen: four decimal places at 1 and above, six below 1, and scientific notation past a billion or below a ten-thousandth. 100 N·m is really 73.75621492772655 lb·ft and is shown as 73.7562.
  • A round trip through a displayed figure loses the digits you cannot see. Convert 100 N·m and you get 73.7562 lb·ft. Type that figure back in and you get 99.99997976 N·m, not exactly 100. The panel still shows 100, because the drift sits below what four decimal places can display, but it is there. Converting from the original figure each time avoids stacking it.
  • Newton metres and joules share a dimension but not a meaning. No converter on this page will turn one into the other, because the equality is dimensional rather than physical.
  • Negative values convert, and keep their sign. A sign on a torque is direction, not an error, so nothing is rejected and nothing is silently made positive. Zero converts to zero in every unit.
  • An empty box is missing data, not zero. Clearing the field leaves the panel awaiting input rather than reporting a confident 0. Text that is not a number gets a message asking for a numeric value.
  • Extreme values stop rather than overflow. Both the figure you type and the value it becomes in newton metres are checked, because a finite number of kilonewton metres can stop being finite once it is multiplied out. Past that point the panel says the value is too large or too small to convert reliably instead of printing Infinity.
  • The table is all or nothing. If any one of the six units would overflow, none of them is shown. A table where some rows are numbers and others are dashes would read as though the dashed units did not apply.

Which unit to reach for

  • N·m is the SI unit and the one most current service literature uses, metric or not.
  • lb·ft is the customary automotive and structural unit in the United States, and the one most torque wrenches sold there are marked in.
  • lb·in and oz·in are for small fasteners, where pound-feet would be an awkward fraction: instrument screws, eyeglass hinges, electronics assembly.
  • kN·m turns up in structural and heavy machinery work, where newton metres would run to six figures.
  • kgf·m is legacy, not SI, and appears mostly on older Japanese and European manuals that were never reissued.

Your figures stay in the page

The value and units you enter are processed by this page in your browser. They are not sent to a server, not stored after you close the tab, and not visible to anyone else. There is no account and nothing to sign up for.

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Sources

  • The defining constants behind every factor on this page: NIST Special Publication 811, whose footnotes give the pound-force as exactly 4.448 221 615 260 5 N and whose Appendix B marks the foot exact at 0.3048 m and standard gravity exact at 9.806 65 m/s². Everything else here is a product of those three. Verified 2026-08-15, and re-checked against the published table on 2026-08-18.
  • That torque is not written in joules: NIST Special Publication 330, the United States edition of the SI Brochure, which states that although torque has the same dimension as energy, the joule is never used for expressing torque. This is a different document from the one behind the numbers above, and it is the one that supports this particular claim. Verified 2026-08-18.

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Frequently asked questions

1 N·m is 0.737562149277 lb·ft, so a newton metre is a little under three quarters of a pound-foot. Going the other way, 1 lb·ft is 1.355817948331 N·m. Those two numbers are reciprocals of each other, which is why the converter never needs a separate factor for each direction.

How hard something is being twisted about an axis. It is a force multiplied by the distance from the axis at which that force acts, which is why every torque unit is a force unit paired with a length unit: the newton metre pairs the newton with the metre, the pound-foot pairs the pound-force with the foot. The same force applied twice as far from the pivot produces twice the torque, which is the whole reason a longer wrench is easier.

For torque, yes. A pound-foot is a force of one pound-force acting at a distance of one foot, and the two words get written in either order: lb-ft, lb·ft, ft-lb, ft·lb, ft lbs, foot-pounds. Service manuals and torque wrenches use all of them for the same quantity. This page labels the unit lb·ft and the number is the same whichever spelling you arrived with.

Multiply by 0.737562149277. A 100 N·m spec is 100 × 0.737562149277 = 73.7562 lb·ft. Going back, multiply the pound-feet by 1.355817948331 instead: 50 lb·ft × 1.355817948331 = 67.7909 N·m. If you only need a rough figure in your head, three quarters is close enough to the first factor and four thirds to the second.

They have the same dimensions, so the arithmetic looks interchangeable, but they describe different quantities. A joule measures energy or work done; a newton metre used for torque measures how hard something is being twisted, and no energy has to be transferred for a torque to exist. NIST puts it plainly in its edition of the SI brochure: even though torque has the same dimension as energy, the joule is never used for expressing torque.

It is not measured, it is defined. A foot is exactly 0.3048 metres and a pound-force is exactly 4.4482216152605 newtons, and multiplying two exact decimals gives another one: a pound-foot is exactly 1.3558179483314004 newton metres. Its reciprocal is not exact, because dividing by that number does not terminate. It runs 0.737562149277265363878..., and 0.737562149277 is where this page stops quoting it. NIST publishes the same factor rounded to seven figures as 1.355 818.

One direction is exact and the other is not, which is worth separating. Because the foot and the pound-force are both defined in SI units rather than measured against a physical object, the pound-foot is exactly 1.3558179483314004 newton metres with no experimental uncertainty at all. The factor going the other way is that number divided into 1, which does not terminate, so 0.737562149277 is a rounding rather than a definition. Either way the display rounds again: results are shown to four decimal places, so 100 N·m appears as 73.7562 lb·ft rather than 73.75621492772655.

Because a torque spec is never that precise. The converter shows four decimal places for values of 1 or more, six for values below 1, and switches to scientific notation past a billion or below a ten-thousandth. The arithmetic itself runs at full double precision throughout and rounds only on the way to the screen, so the rounding never feeds back into the next conversion.

Yes. In engineering work the sign of a torque says which way it turns, so a negative value converts exactly like a positive one and keeps its sign. If you only care about how tight a bolt is, drop the sign and read the magnitude.

Small fasteners are specified in the smaller units because pound-feet would be an awkward fraction. Eyeglass hinges, instrument screws and electronics assembly are usually in ounce-inches or pound-inches; automotive and structural specs are in pound-feet or newton metres. There are exactly 12 lb·in in 1 lb·ft and 16 oz·in in 1 lb·in.

An older metric unit still seen on Japanese and European service literature, written kgf·m or sometimes just kg-m. It is the torque produced by standard gravity acting on one kilogram at one metre, so 1 kgf·m is exactly 9.80665 N·m and about 7.233 lb·ft. It is not an SI unit and modern specifications use newton metres, but this converter supports it because old manuals do not get reprinted.

Torque is a twist and power is a rate, so they are different quantities rather than different units of one thing, and no factor converts between them. Power is torque multiplied by how fast the shaft is turning, which means the same torque at twice the speed is twice the power. This page converts torque units only, and no page on this site works out power from a torque and an engine speed. If what you have is already a power figure and you only need it in different units, the power converter handles watts, kilowatts, mechanical horsepower and BTU per hour.

It converts until the arithmetic itself runs out of room, and then it stops rather than printing nonsense. Both the figure you type and the value it becomes in newton metres are checked, because a number that is perfectly finite in kilonewton metres can overflow once it is multiplied out. When that happens the panel says the value is too large or too small to convert reliably instead of showing Infinity.

Nothing is converted and no figure is shown. An empty box leaves the panel awaiting input, and text that is not a number gets a message asking for a numeric value. A blank field is treated as missing rather than as zero, so the converter never reports a confident 0 you did not ask for.

Yes. It is free to use with no account, no sign-up, and no limit on conversions. Everything runs inside this page in your browser.