Torque Unit Converter

1 lbf·ft = 1.3558 N·m and 1 kgf·m = 9.80665 N·m

Torque is the turning effect of a force. You get it by multiplying the force by the distance from the axis to the point where the force acts, so every torque unit is a force unit times a length unit. A newton meter (N·m) is 1 N applied 1 m from the axis. A pound-force foot (lbf·ft, also written lb-ft or ft-lb) is the weight of 1 pound applied 1 ft from the axis, and a kilogram-force meter (kgf·m) is the weight of a 1 kg mass (9.80665 N) applied 1 m from the axis.

The converter above changes thirteen torque units from three families (newton, kilogram-force and pound-force) at once. Type a value into any field and the others follow. It also shows the force needed at a given point on a wrench handle and, once you enter an rpm, the power in kW, PS and hp. For example, 400 N·m is 295.02 lbf·ft, and 100 lbf·ft is 135.58 N·m.

When you need to convert

• Setting a torque wrench: the wrench scale may read lbf·ft, lbf·in (in-lb) or N·m, and the specification you follow may use a different one. 1 lbf·ft is 12 lbf·in, so mixing the two scales means tightening 12 times too hard or too soft, and 400 N·m has to be dialed as 295.02 lbf·ft.
• Reading Korean and Japanese spec sheets: the Hyundai Sonata The Edge lists its 2.0 gasoline engine at '20.0 kgf·m / 4,800 rpm'. That is 196.13 N·m, or 144.66 lbf·ft. The Toyota Japan spec table gives the Yaris hybrid engine (M15A-FXE) as '120 (12.2)': N·m first, with kgf·m in brackets, and 120 N·m is 88.51 lbf·ft.
• Wheel nuts: the Hyundai Avante owner's manual gives the recommended wheel nut torque as 11-13 kgf·m and no other unit. That is 107.87 to 127.49 N·m, or 79.56 to 94.03 lbf·ft. Check the figure and the unit in your own vehicle's manual before you set the wrench.
• Servos and small motors: the Hitec HS-311 servo lists max torque as 3.0 to 3.7 kg·cm and as 41.66 to 51.38 oz-in at 4.8 to 6.0 V. The Mabuchi FF-260PA-3057 motor lists mN·m and g·cm side by side. Here kg·cm and g·cm mean kgf·cm and gf·cm.
• Estimating power from engine torque: power is torque times rotational speed. Put the spec-sheet torque and the rpm where it occurs into the power calculator and you get the power at that point in hp, PS or kW.

How to use it

1. Enter the value you know in the matching field. The board groups the units into the Newton (SI), Kilogram-force and Pound-force families (three columns on wide screens, stacked on narrow ones), and within each family the units run from large to base to small. Thousands separators such as 1,234.5 are fine.
2. The field you typed in becomes the reference (dark border) and the other eleven change. A field that holds a rounded value shows '≈' before the number. The smallest SI field can be switched between mN·m and dyn·cm.
3. 'Decimal places' offers 0, 1, 2, 4 and 6. The sentence under the fields gives your value in each family's base unit (N·m, kgf·m and lbf·ft), in full when the decimal ends and otherwise to six decimals, and the formula line under it shows which factor was used to multiply or divide.
4. In 'Wrench view', enter the distance from the bolt center to your hand, or drag the weight, and the force needed at that point appears in lbf and N. The orange numbers under the handle are the force at each mark.
5. Under 'Enter rpm to get power', type an rpm and the converter calculates the power this torque delivers at that speed in kW, PS and hp.
6. 'Common values' puts a value into the fields when you click it. 'Copy result' copies the twelve fields plus the wrench and power results, and 'Copy link' copies a link that contains your current input.

How the conversion works

Every unit is first converted to N·m, then divided by the N·m value of one target unit. Those values come from the defined force units (1 kgf = 9.80665 N, 1 lbf = 0.45359237 kg × 9.80665 m/s²) multiplied by the defined length units (1 ft = 0.3048 m, 1 in = 0.0254 m), and they match the NIST conversion factors.

1. lbf·ft → N·m: lbf·ft × 1.3558179 (100 lbf·ft → 135.58 N·m)
2. N·m → lbf·ft: N·m ÷ 1.3558179 (400 N·m → 295.02 lbf·ft)
3. kgf·m → N·m: kgf·m × 9.80665 (20.0 kgf·m → 196.13 N·m)
4. N·m → kgf·m: N·m ÷ 9.80665 (100 N·m → 10.20 kgf·m)
5. kgf·cm → ozf·in: kgf·cm × 0.0980665 ÷ 0.0070615 (3.7 kgf·cm → 51.38 ozf·in)

The converter keeps the factors as exact fractions and rounds only once, at the end. That is why 1 kgf·m = 9.80665 N·m shows as 9.8067 at four decimals, with no trailing error from decimal arithmetic mixed into the result.

lbf·ft, N·m and kgf·m conversion tables

Torque = force × distance: a longer wrench needs less force

For the same torque, the force you need falls in proportion to how far from the bolt you push. 100 lbf·ft at 12 in from the bolt center needs 100 lbf, and at 18 in it needs only 66.7 lbf. The unit name says the same thing: 100 lbf·ft is a 100 lb weight hanging at the end of a 1 ft bar.

This is also why 'what is 1 N·m in kg?' has no single answer. Torque is a force multiplied by a distance, so you need to know the distance. 1 N·m is a force of about 0.102 kgf (0.225 lbf) at the end of a 1 m bar, or about 1.02 kgf at 10 cm. The wrench view above does this calculation and draws it, assuming the force is applied at right angles to the handle.

Torque and power (horsepower)

Power is torque times rotational speed. With torque in N·m and speed in rpm, power in watts = torque × 2π × rpm ÷ 60. Reduced to one unit pair at a time, the torque number and the power number are equal at the speeds below.

The Hyundai Sonata The Edge 2.0 gasoline engine makes its maximum torque of 20.0 kgf·m (144.66 lbf·ft) at 4,800 rpm. At that point the power is 144.66 × 4,800 ÷ 5,252.1 = about 132.2 hp, which is 20.0 × 4,800 ÷ 716.2 = about 134.0 PS. Its maximum power of 160 PS comes at a higher 6,500 rpm, where the torque works back to 160 × 716.2 ÷ 6,500 = about 17.6 kgf·m (127.5 lbf·ft). The two peaks are at different speeds because power keeps rising with rpm for a while even as torque falls.

The same formula works for small motors. The Mabuchi FF-260PA-3057 data sheet gives 6,790 r/min, 2.39 mN·m and 1.69 W at maximum efficiency, and 2.39 mN·m × 2π × 6,790 ÷ 60 comes to 1.70 W, which differs from the sheet only by rounding.

Common mistakes

• Reading the kgf in kgf·m as a mass in kg: a kilogram-force is the weight of 1 kg under standard gravity, 9.80665 N. So 1 kgf·m is 9.80665 N·m, not 1 N·m. The 'kg·cm' in servo ratings is shorthand for kgf·cm.
• Mixing lbf·ft and lbf·in: 1 lbf·ft = 12 lbf·in. Small fasteners are often specified in in-lb, and picking the wrong scale on the wrench makes you tighten 12 times too hard or too soft.
• Confusing N·cm and N·m: 1 N·cm = 0.01 N·m. Read a small driver's N·cm (cN·m) value as N·m and it is 100 times too large.
• Writing N·m as J (joule): torque and energy have the same dimension, but NIST specifies the newton meter as the unit of torque and the BIPM SI Brochure says the joule is never used for expressing torque.
• Treating lb-ft and ft-lb as different values: for torque both mean the same size, 1.3558 N·m. NIST writes lbf·ft, and ft·lbf is also used as a unit of work and energy of the same size, so read it by context.
• Assuming tf·m and kip·ft are the same size: both are 'thousand' units, but 1 tf·m = 9,806.65 N·m and 1 kip·ft is about 1,355.82 N·m, more than 7 times smaller.

Limits

• This converter only changes units. The torque to use on a given bolt is set by the vehicle or part manufacturer, and the recommended value can change with thread lubrication, reused bolts and the tightening order.
• kgf, tf and gf, and lbf, kip and ozf, are defined with standard gravity, 9.80665 m/s². They convert to the same values wherever you are, regardless of the gravity measured at your location.
• The force in the wrench view assumes a horizontal handle and a force at right angles to it. Pushing at an angle takes more force for the same torque.
• The power calculation multiplies the torque you entered by the speed, assuming the engine makes that torque at that rpm. Real engine torque changes with rpm, so a maximum-torque value and its rpm give the power at that one point only.
• A negative number is taken to mean the direction of turning and the sign is carried through. The wrench drawing and the power use the magnitude only.
• When transferring a value to a torque wrench, the wrench's smallest scale division and its calibration matter more than the decimal places shown on screen.

Basis: the factors are the defined values in NIST SP 811 Appendix B.9 and do not change from year to year. The spec sheets, owner's manual and data sheets were checked against the originals on 21 October 2026.

Sources

• 01NIST SP 811 Appendix B.9 — Factors for units listed by kind of quantityMOMENT OF FORCE or TORQUE: dyn·cm 1.0E-07, kgf·m 9.80665, ozf·in 7.061552E-03, lbf·ft 1.355818, lbf·in 1.129848E-01 N·m · FORCE: kgf 9.80665 N, kip (1,000 lbf) 4.448222E+03 N
• 02NIST SP 811 Chapter 4, 4.2.2The SI unit of moment of force is the newton meter (N·m), not the joule (J)
• 03BIPM — The International System of Units (SI Brochure), 9th editionTable 6: the unit of moment of force (torque) is N m · although torque has the same dimension as energy, the joule is never used for expressing torque
• 04Hyundai Motor — Sonata The Edge (Korean site)Gasoline 2.0: max power 160 PS / 6,500 rpm, max torque 20.0 kgf·m / 4,800 rpm · 2.5 turbo 43.0 kgf·m / 1,650–4,000 rpm
• 05Hyundai Motor owner's manual — Avante (CN8) 2027 (Korean)Recommended wheel nut torque 11-13 kgf·m (given in kgf·m only)
• 06Toyota Japan — Yaris specification table (主要諸元表)Max torque N･m (kgf･m) / r.p.m.: 120 (12.2) / 3,800–4,800, hybrid engine M15A-FXE column
• 07Hitec — HS-311 Standard Economy ServoMax torque 3.0–3.7 kg·cm = 41.66–51.38 oz-in at 4.8–6.0 V
• 08Mabuchi Motor — FF-260PA performance dataFF-260PA-3057: at max efficiency 6,790 r/min, 2.39 mN·m (24.3 g·cm), 1.69 W · stall 18.4 mN·m (188 g·cm)

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