Torque Converter

Convert between SI and imperial torque units (newton-metre, kilonewton-metre, kilogram-force metre, kilogram-force centimetre, pound-foot, pound-inch, ounce-inch) with NIST-grade exact factors anchored to CGPM 1901 standard gravity and the 1959 international yard and pound.

From

Value

lb·ft

Result

1.35582 N·m

1 lb·ft= 1.355818 N·m

Decimals

All units

Unit	Value
Newton-meter (N·m)	1.35582
Kilonewton-meter (kN·m)	0.00135582
Kilogram-force meter (kgf·m)	0.138255
Kilogram-force centimeter (kgf·cm)	13.8255
Pound-foot (lb·ft)	1
Pound-inch (lb·in)	12
Ounce-inch (oz·in)	192

Force Converter Pressure Converter

Updated: June 13, 2026

Torque converter. SI, gravitational and US customary torque units with NIST-exact factors.

A torque converter changes a value from one unit of torque to another using exact NIST factors anchored to the SI newton-metre. So 1 lb·ft = 1.3558179483314003 N·m and 1 kgf·m = 9.80665 N·m exact, with every pair in the table tagged exact via the 1959 yard-and-pound and CGPM 1901 standard gravity.

What Is a Torque Converter?

Torque and energy are both measured in the same base unit — the newton-metre — and yet they are two completely different physical quantities. Torque is a twist (a force applied at a distance from a pivot, written N·m or lb·ft); energy is work done (a force pushing something along a distance, written joules or ft·lb). The arithmetic is identical because both reduce to kg·m²/s², but you can never add 50 N·m of torque to 50 J of energy, even though the units look interchangeable. A serious torque converter has to keep that line sharp — and that is why every unit here is labelled as torque and routed through one base.

The trap that wastes the most wrenches is closer to home. In the US, lug-nut and engine specs are written in pound-feet (lbf·ft), but a lot of small torque drivers read in pound-inches (lbf·in) — and 1 lbf·ft is exactly 12 lbf·in. Set a wrench to "80" on the wrong scale and you are off by a factor of 12 in either direction: either you barely snug the bolt or you shear it. The same crash happens between systems — a Japanese service manual that says 25 N·m and a wrench calibrated in lb·ft (where 25 reads as ~34 N·m) will over-torque the joint. This converter exists to do that translation once, exactly, so the number on your wrench matches the number in the spec.

Every value entered here is routed through a single base unit — the newton-metre (N·m), the engine's `toBase` of 1 — and multiplied by each unit's defined factor: 1 kilonewton-metre is exactly 1000 N·m, 1 kilogram-force metre is exactly 9.80665 N·m, 1 kilogram-force centimetre is exactly 0.0980665 N·m, 1 pound-foot is exactly 1.3558179483314003 N·m, 1 pound-inch is exactly 0.11298482902761668 N·m (which is precisely lb·ft ÷ 12), and 1 ounce-inch is exactly 0.007061551814226043 N·m (precisely lb·in ÷ 16). These are not engineering approximations; they are exact rational products of three fixed values — the SI newton-metre (1 kg·m²/s² since the 2019 SI revision), the 1959 International Yard and Pound Agreement (1 lb = 0.45359237 kg, 1 ft = 0.3048 m, 1 in = 0.0254 m, all exact), and the 3rd CGPM (1901) declaration that standard gravity is exactly 9.80665 m/s².

The converter supports seven units across two families. The SI family (newton-metre, kilonewton-metre) dominates modern engineering specifications, every motor torque rating outside the US, every aerospace turbine bolt spec, and physics literature. The gravitational family (kilogram-force metre, kilogram-force centimetre, pound-foot, pound-inch, ounce-inch) is the legacy of pre-SI engineering practice but is still standard in three living domains: US automotive and motorcycle service manuals (lb·ft and lb·in on every lug nut and spark plug spec), Japanese and Taiwanese torque wrenches (Tohnichi, KTC and Snap-on Asia routinely publish in kgf·cm and kgf·m), and RC servo and small-motor datasheets (oz·in is the canonical small-torque rating). The most common everyday pair is N·m ↔ lb·ft for any cross-border automotive or motorcycle spec. All seven units have exact rational factors and every pair is tagged exact, with the precision selector exposing up to 15 decimal digits — the full IEEE-754 double mantissa.

How to Convert Between Torque Units

Every torque conversion is one multiplication and one division through the newton-metre. The general formula is:

y = x \cdot \frac{a_{\text{from}}}{a_{\text{to}}}

where x is your input value, a_from is the source unit's factor to newton-metres, and a_to is the target unit's factor to newton-metres. To do it by hand:

1. Look up the source-to-newton-metre factor. For pound-foot, a_from = 1.3558179483314003.

2. Multiply the input by that factor to get newton-metres. 100 lb·ft × 1.3558179483314003 = 135.58179483314 N·m.

3. Look up the target-to-newton-metre factor. For newton-metres, a_to = 1.

4. Divide the newton-metre value by the target factor. 135.58179483314 ÷ 1 = 135.58179483314 N·m.

The same procedure works for every supported unit. Going from kilogram-force metres to newton-metres: 1 kgf·m × 9.80665 N·m/(kgf·m) = 9.80665 N·m exact (the cleanest gravitational-to-SI conversion in the table, with the CGPM-1901 factor 9.80665 dropping out unchanged). Going from pound-inch to newton-metres: 1 lb·in × 0.11298482902761668 = 0.11298482902761668 N·m, which is exactly lb·ft ÷ 12 (because there are 12 inches in a foot). Going from ounce-inch to pound-inch: 1 oz·in × 0.007061551814226043 ÷ 0.11298482902761668 = 0.0625 lb·in exactly (= 1/16, since there are 16 ounces in a pound).

To use this calculator, pick the source unit from the "From" dropdown, type a value, then pick the target unit from the "To" dropdown. The result updates on every keystroke. Click the result card to copy it to the clipboard. Use the precision selector to switch between auto (6 significant figures), or a fixed 0, 2, 4, 6, 10 or 15 decimals. Auto-precision switches to scientific notation when the result is larger than 10¹² (one trillion) or smaller than 10⁻³, so converting a wind-turbine tower bolt spec (~15 kN·m → ~11 063 lb·ft → ~132 749 lb·in) still renders readably at every step. The "exact" badge appears next to every torque result, because every unit in this set has a rational, definitionally exact factor to the newton-metre.

Most-Searched Torque Conversions at a Glance

From	To	Value	Exact?
1 N·m	Pound-foot	0.7375621493 lb·ft	yes
1 N·m	Pound-inch	8.8507457913 lb·in	yes
1 lb·ft	Newton-metre	1.3558179483 N·m	yes
100 lb·ft (US lug nut)	Newton-metre	135.58 N·m	yes
1 lb·ft	Pound-inch	12 lb·in	yes
1 lb·in	Pound-foot	0.0833333 lb·ft	yes
6 N·m (carbon bike stem)	Pound-inch	53.10 lb·in	yes
1 kgf·m	Newton-metre	9.80665 N·m	yes
1 kgf·m	Pound-foot	7.2330139 lb·ft	yes
1 N·m	Kilogram-force metre	0.1019716 kgf·m	yes
400 oz·in (RC servo)	Newton-metre	2.82 N·m	yes

Torque Conversion Formula

y = x \cdot \frac{a_{\text{from}}}{a_{\text{to}}}

$y$ = The converted value, expressed in the target unit of torque.
$x$ = The input value, expressed in the source unit of torque.
$a_{\text{from}}$ = Factor that converts the source unit to newton-metres (e.g. 9.80665 for kgf·m, 1.3558179483314003 for lb·ft, 0.0980665 for kgf·cm).
$a_{\text{to}}$ = Factor that converts the target unit to newton-metres (e.g. 1000 for kN·m, 0.11298482902761668 for lb·in, 0.007061551814226043 for oz·in).

The formula is a two-step pivot through the newton-metre base unit. The factor table this calculator uses is sourced from NIST SP 811 Appendix B.8 (which lists kgf·m in boldface as exact at 9.80665, lb·ft at 1.355818, lb·in at 0.1129848 and ozf·in at 7.061552 × 10⁻³) and anchored to four exact upstream definitions — the SI newton-metre, the 1959 International Yard and Pound Agreement (1 lb = 0.45359237 kg, 1 ft = 0.3048 m, 1 in = 0.0254 m, all exact), and the 3rd CGPM (1901) declaration that g_n = 9.80665 m/s² exact:

Newton-metre (N·m): 1 N·m (exact, SI derived unit; 1 N·m ≡ 1 kg·m²/s²)
Kilonewton-metre (kN·m): 1000 N·m (exact, SI)
Kilogram-force metre (kgf·m): 9.80665 N·m (exact, = 1 kgf × 1 m; CGPM 1901 boldface in NIST SP 811)
Kilogram-force centimetre (kgf·cm): 0.0980665 N·m (exact, = kgf·m / 100)
Pound-foot (lb·ft): 1.3558179483314003 N·m (exact, = 4.4482216152605 N × 0.3048 m, IEEE-754 product of NIST exact rationals; NIST prints 1.355818 rounded)
Pound-inch (lb·in): 0.11298482902761668 N·m (exact, = lb·ft / 12 = 4.4482216152605 N × 0.0254 m; NIST prints 0.1129848 rounded)
Ounce-inch (oz·in): 0.007061551814226043 N·m (exact, = lb·in / 16; the 16 is a power of 2, so the division is bit-exact in IEEE-754; NIST prints 7.061552e-3 rounded)

For the N·m → lb·ft direction the calculator displays the irrational quotient 1 / 1.3558179483314003 = 0.7375621492772653… lb·ft/N·m. Most casual converters print 0.7376 and stop there; this one will print as many digits as the precision selector requests, up to 15. The same applies to the N·m → lb·in ratio: 1 / 0.11298482902761668 = 8.850745791327185… lb·in/N·m (the constant every torque-screwdriver datasheet uses). Every result is tagged exact because both endpoints are exact rationals — the irrationality is in the printed form, not in the underlying definition.

Worked Torque Conversion Examples

100 lb·ft to N·m (the lug nut conversion every mechanic does)

Set From = Pound-foot, To = Newton-meter, Value = 100. The formula gives 100 × 1.3558179483314003 = 135.58179483314 N·m exact. At auto-precision the result reads 135.582 N·m (6 significant figures). A typical passenger-car lug nut spec lands in the 80–100 lb·ft window (108–135 N·m), with most Toyota Corolla-class sedans calling for 80 lb·ft = 108.47 N·m and Honda Accord-class mid-sizes calling for 100 lb·ft = 135.58 N·m. This is the conversion every US mechanic working on a Japanese-imported service manual does daily: the spec is written in N·m, the torque wrench is calibrated in lb·ft, and the result has to be exact because lug-nut over-tightening warps brake rotors. The 0.0006% gap between the casual 1.3558 rounding and the exact 1.3558179483314003 figure drifts by ~0.0018 N·m over 100 lb·ft — invisible on any wrench, but it accumulates.

1 kgf·m to N·m (the JDM service-manual conversion)

Set From = Kilogram-force meter, To = Newton-meter, Value = 1. The formula gives 1 × 9.80665 = 9.80665 N·m exact. This is the single cleanest gravitational-to-SI conversion in the whole table because the CGPM-1901 declaration fixes standard gravity at exactly 9.80665 m/s², no rounding involved. Older Japanese motorcycle service manuals (Honda CB-series, Yamaha FZ-series from the 1980s and 1990s) routinely specify cylinder-head bolts at 5.5 kgf·m = 53.94 N·m = 39.78 lb·ft and camshaft cap bolts at 1.6 kgf·m = 15.69 N·m = 11.57 lb·ft. The kgf·m unit survived in Asian and European technical literature long after BIPM deprecated it because workshop torque wrenches manufactured in Japan still ship with kgf·m and kgf·cm scales etched alongside N·m.

6 N·m to lb·in (the bicycle stem-bolt conversion)

Set From = Newton-meter, To = Pound-inch, Value = 6. The formula gives 6 ÷ 0.11298482902761668 = 53.10 lb·in at auto-precision, more precisely 53.104474747963 lb·in at 12 decimals. A typical threadless bike stem steerer-clamp bolt (the bolt that holds your handlebar to the fork) spec'd by Shimano, Deda or FSA falls between 5 N·m and 8 N·m — too small for a click wrench calibrated in lb·ft, exactly the sweet spot for an inch-pound torque screwdriver. Park Tool publishes their bike-shop reference in N·m with an in-lb conversion column for exactly this reason. Over-tightening a carbon stem above ~8 N·m crushes the steerer tube; under-tightening lets the bar rotate in the clamp. The conversion is exact because both endpoints are exact rationals; the inch-pound wrench tolerance (typically ±4% per ISO 6789) is a much bigger error budget than any rounding of the conversion factor.

400 oz·in to N·m (the RC servo torque rating)

Set From = Ounce-inch, To = Newton-meter, Value = 400. The formula gives 400 × 0.007061551814226043 = 2.8246207256904 N·m exact, or about 2.82 N·m at auto-precision. A high-end standard-size hobby servo (Futaba, Hitec, JR) rated at "400 oz·in @ 6V" delivers roughly 2.82 N·m of holding torque — enough to drive a 1/8-scale RC car's steering linkage or a model aircraft's elevator under aerodynamic load. The oz·in unit dominates US-market RC servo datasheets, while Asian datasheets for the same servos quote the equivalent in kgf·cm: 400 oz·in × 0.007061551814226043 ÷ 0.0980665 = 28.80 kgf·cm, which is why hobby-grade specs almost always list both numbers side by side.

15 kN·m wind-turbine tower bolt to lb·ft (the kilonewton-metre scale)

Set From = Kilonewton-meter, To = Pound-foot, Value = 15. The formula gives 15 × 1000 ÷ 1.3558179483314003 = 11 063.43 lb·ft at auto-precision. The latest offshore wind-turbine tower joints have torque targets climbing from the historical 5 kN·m (~3 690 lb·ft) limit to 12 kN·m (~8 851 lb·ft) and even 15 kN·m (~11 063 lb·ft) on the biggest 15-MW class machines. At this scale conventional click wrenches and torque multipliers cannot reach the spec; the work is done with hydraulic torque tensioners that pull the bolt directly. Wind turbine fasteners are typically Grade 10.9 or 12.9 high-tensile steel, and the difference between an under-torqued and a yielded bolt is a few percent on the spec sheet. The result is tagged exact because both endpoints (kN·m, lb·ft) are defined by exact rational factors.

Comparative table: 1 unit in newton-metres and pound-foot

Unit	Value in N·m	Value in lb·ft	Value in lb·in	Value in kgf·cm	Exact?
Ounce-inch (oz·in)	0.0070615518	0.0052083 (= 1/192)	0.0625 (= 1/16)	0.072007	yes
Kilogram-force cm (kgf·cm)	0.0980665	0.0723301	0.867962	1	yes
Pound-inch (lb·in)	0.1129848290	0.0833333 (= 1/12)	1	1.152124	yes
Newton-metre (N·m)	1	0.7375621493	8.8507458	10.19716	yes
Pound-foot (lb·ft)	1.3558179483	1	12	13.82550	yes
Kilogram-force m (kgf·m)	9.80665	7.233014	86.79617	100	yes
Kilonewton-metre (kN·m)	1000	737.5621493	8850.7458	10197.16	yes

Three definitional shortcuts worth memorising: 1 lb·ft = 12 lb·in exactly (the inch-per-foot ratio), 1 lb·in = 16 oz·in exactly (the ounce-per-pound ratio, both powers of 2 so bit-exact in IEEE-754), and 1 kgf·m = 100 kgf·cm exactly (the centimetre-per-metre ratio). All other rows are exact rationals that follow from these definitions and the SI newton-metre. The N·m ↔ lb·ft 1.3558179483 multiplier and its inverse 0.7375621493 are the two constants that crack the entire automotive cross-system.

Torque Converter — Frequently Asked Questions

How many N·m in 1 lb·ft?

Exactly 1.3558179483314003 N·m. The number is not measured; it is defined, as the product of 4.4482216152605 N (the exact pound-force from IYP 1959 and CGPM 1901) and 0.3048 m (the exact international foot). Most casual references quote 1.3558 or 1.356, which are roundings. For metrology or aerospace work, use the full value.

How many lb·in in 1 lb·ft?

Exactly 12 lb·in. The relationship is purely geometric: 1 foot equals 12 inches by definition, so 1 pound-force × 1 foot = 1 pound-force × 12 inches = 12 lb·in exactly. Torque-screwdriver datasheets in the US use lb·in for small fasteners (electronics, bicycle stems, plumbing fittings) because lb·ft values smaller than ~1 are awkward to read on a wrench scale. Setting a wrench to the wrong scale is a 12× error.

What is the difference between lb-ft and ft-lb?

Physically, when both refer to torque, lb·ft and ft·lb describe the same quantity: a pound of force acting at a 1-foot lever arm. The distinction is naming convention. SAE, NIST and BIPM recommend writing lb·ft (force first, then length) for torque, to keep it visually separate from the ft·lb (foot-pound) used as a unit of work or energy in physics. Dimensionally they share the same SI base units, but torque is a vector (cross product τ = r × F) while energy is a scalar (dot product W = F · d).

Are newton-metre and joule the same?

Dimensionally yes; conceptually no. Both reduce to kg·m²/s² in SI base units. But the newton-metre is reserved for torque (rotational force, a vector) and the joule for energy or work (a scalar). The SI Brochure explicitly notes that torque should be expressed in newton-metres, not joules. Writing 50 J of torque is wrong even though the arithmetic is identical to 50 N·m of torque — the unit signals what kind of quantity you are measuring.

What is 1 kgf·m in newton-metres?

Exactly 9.80665 N·m. The CGPM-1901 declaration fixes standard gravity at exactly 9.80665 m/s², so 1 kilogram-force is exactly 9.80665 N and 1 kgf·m is exactly 9.80665 N·m. NIST SP 811 prints this factor in boldface as one of the cleanest gravitational-to-SI conversions in the entire torque section. The workshop shortcut "×10" is about 1.9% high.

Why do Japanese torque wrenches use kgf·cm?

Because kgf·cm and kgf·m were the dominant Japanese industrial torque units before the BIPM SI revisions, and they survived in workshop practice long after BIPM deprecated them. Tohnichi, KTC and Snap-on KRA (the Asia-spec line) all ship click and dial torque wrenches with kgf·cm scales etched alongside N·m and lb·in. Asian servo and small-motor datasheets quote torque in kgf·cm or g·cm; Japanese motorcycle service manuals from the 1980s–1990s spec everything in kgf·m. 1 kgf·cm = 0.0980665 N·m exact = 0.86796 lb·in.

Is foot-pound the same as pound-foot?

Only when both are used to mean torque — and that is a convention, not a guarantee. The strict technical reading is that pound-foot (lb·ft) is the torque unit and foot-pound (ft·lb) is the unit of work or energy. Both use the same arithmetic (lbf × ft = 1.3558 N·m or J), but they describe different physical quantities. In a sentence like "the engine produces 300 ft-lb of torque", the SAE-correct version would be "300 lb-ft of torque". This calculator labels torque values in lb·ft throughout to keep the distinction sharp.

What is a typical lug nut torque in N·m and lb·ft?

Passenger cars typically call for 100–150 lb·ft (about 135–203 N·m), with compact sedans (Toyota Corolla, Honda Civic) near 80 lb·ft (108 N·m) and mid-size cars (Honda Accord, Toyota Camry) near 100 lb·ft (135 N·m). Light trucks and SUVs run higher, often 120–150 lb·ft (163–203 N·m). Always consult the owner's manual — aluminium wheels generally take ~10–15% less than steel wheels, and over-tightening warps brake rotors before it strips threads.

Why does 1 N·m to lb·ft give an irrational decimal?

Because the exact definition runs the other way: 1 lb·ft is exactly 1.3558179483314003 N·m. The inverse 1/1.3558179483314003 = 0.7375621492772653… lb·ft/N·m is mathematically irrational — there is no last digit, only a longer truncation. Engineering tables almost always print 0.7376; this calculator will show whatever precision you ask for, up to 15 decimal digits.

What unit do wind-turbine bolts use?

Modern offshore wind-turbine tower joints have torque targets in the 5 to 15 kN·m range (kilonewton-metres), with the largest 15-MW-class machines pushing past 12 kN·m on critical flange bolts. At that scale conventional click wrenches and hand torque multipliers are useless — the work is done with hydraulic torque tensioners that pull the bolt axially. 15 kN·m converts to about 11 063 lb·ft or 132 749 lb·in; the kN·m unit is the only one that stays readable at this scale.

How accurate are the torque conversion factors?

Every factor in this converter is exact. The newton-metre and kilonewton-metre are exact by SI definition. The kilogram-force metre is exact by CGPM-1901 standard gravity (9.80665 N per kgf × 1 m). The pound-foot, pound-inch and ounce-inch are exact products of NIST-exact rationals: 1 lb·ft = 4.4482216152605 N × 0.3048 m = 1.3558179483314003 N·m, with zero rounding error. NIST prints rounded forms, but every factor here is the full IEEE-754 product.

Is this torque converter free and can I embed it?

Yes. The calculator requires no account, runs entirely in your browser, and shows no ads. The embeddable iframe version is also ad-free and tracker-free, so you can drop it into automotive workshops, motorcycle and bike-shop service pages, RC and modelling forums, aerospace and wind-energy engineering portals, or physics-education sites without exposing readers to third-party trackers.

Sources & References

Content verified by the Smart Calculators Team