Torque is one physical quantity, but a bolt spec rarely arrives in the unit your wrench displays. A Japanese manual quotes 34 N·m, a US dial reads foot-pounds, a small-fastener wrench is graduated in inch-pounds, and an older spec plate may still say kgf·m. Type a number once in any of those units and this converter shows it in all four at once — the arithmetic runs at full precision in your browser, and nothing you type leaves the page.
The toggle pre-fills the conversion direction; the value stays the same torque, re-expressed in the chosen input unit.
Switching units converts the current number in place, so the physical torque never jumps.
Same Torque, Four Units
Newton-metresinput
30
N·m
Foot-pounds
22.13
ft·lb
Inch-pounds
265.52
in·lb
Kilogram-force metres
3.06
kgf·m
the input is already in N·m; other units are derived from it directly
Almost every hand-tightened bolt spec on a passenger car, motorcycle, bicycle, or piece of light equipment lands between 10 and 200 N·m, so this band is where the "quick, what is that in foot-pounds?" question gets asked thousands of times a day. Each row below is computed from the same constants the converter uses — ft·lb = N·m ÷ 1.35582, in·lb = N·m ÷ 0.112985, kgf·m = N·m ÷ 9.80665 — rounded to one decimal for ft·lb and in·lb and two for kgf·m, which is finer than any click wrench can resolve.
| Torque (N·m) | ft·lb | in·lb | kgf·m |
|---|---|---|---|
| 10 | 7.4 | 88.5 | 1.02 |
| 20 | 14.8 | 177.0 | 2.04 |
| 25 | 18.4 | 221.3 | 2.55 |
| 30 | 22.1 | 265.5 | 3.06 |
| 40 | 29.5 | 354.0 | 4.08 |
| 50 | 36.9 | 442.5 | 5.10 |
| 60 | 44.3 | 531.0 | 6.12 |
| 80 | 59.0 | 708.1 | 8.16 |
| 100 | 73.8 | 885.1 | 10.20 |
| 120 | 88.5 | 1062.1 | 12.24 |
| 140 | 103.3 | 1239.1 | 14.28 |
| 150 | 110.6 | 1327.6 | 15.30 |
| 200 | 147.5 | 1770.1 | 20.39 |
Read down the N·m column to find a metric spec, then take the ft·lb value straight to a foot-pound wrench. Read the other direction when a US-written procedure quotes foot-pounds and your dial is metric: 60 N·m ↔ 44.3 ft·lb works both ways.
Foot-pounds and inch-pounds are the same family separated by an exact factor of twelve — no constants, no rounding. The table shows the whole-round-foot values people set most often, plus the metric equivalent so a mixed-unit procedure can be checked in one glance.
| ft·lb | in·lb (exact ×12) | N·m | kgf·m |
|---|---|---|---|
| 10 | 120 | 13.56 | 1.38 |
| 20 | 240 | 27.12 | 2.77 |
| 50 | 600 | 67.79 | 6.91 |
| 100 | 1200 | 135.58 | 13.83 |
| 200 | 2400 | 271.16 | 27.65 |
Two habits make these tables safer than mental arithmetic. First, always sanity check the magnitude before trusting a digit: inch-pound readings should be about twelve times the foot-pound reading, and N·m values about three-quarters of the foot-pound value — if a converted number lands near the unconverted one instead (30 and 34, say), you have used the factor in the wrong direction. Second, when a spec sits between two rows, interpolate by feel rather than precision: the difference between adjacent rows here is smaller than the tolerance of the tool you will set it with.
Core constants
1 ft·lb = 1.35582 N·m
1 in·lb = 1.35582 ÷ 12 = 0.112985 N·m
1 kgf·m = 9.80665 N·m
exact underlying values: 1.3558179… N·m per ft·lb · 12:1 · 9.80665 by definition
Three of these numbers deserve a sentence about where their authority comes from. The foot-pound figure follows from two definitions fixed by the international yard-and-pound agreement: one foot is exactly 0.3048 metres and one avoirdupois pound is exactly 0.45359237 kilograms, which pins one pound-force against the standard gravity of 9.80665 m/s² and gives 1 ft·lb = 1.3558179… N·m — conventionally quoted to six significant figures as 1.35582, the value this page uses, and listed by NIST SP 811 as 1.355818. The inch-pound needs no physics at all, because the inch is a twelfth of the foot, so the 12:1 ratio is exact by definition. And the kilogram-force metre is exact in the opposite sense: the kilogram-force was itself defined as exactly 9.80665 newtons by the 3rd CGPM in 1901, and the BIPM SI Brochure still carries that value today.
Everything else in the table is the reciprocal of those constants, so the only judgement call in the whole system is how many digits to keep. Keep too few and the error compounds when you convert, round, and convert back; keep too many and you imply a precision no torque wrench possesses. The factors below are quoted to six significant figures — more than enough for any mechanical work — with the exact ratios flagged where they exist.
| From | To | Multiply by | Reverse (multiply by) |
|---|---|---|---|
| N·m | ft·lb | 0.737561 | 1.35582 |
| N·m | in·lb | 8.85073 | 0.112985 |
| N·m | kgf·m | 0.101972 | 9.80665 (exact) |
| ft·lb | in·lb | 12 (exact) | 1/12 (exact) |
| ft·lb | kgf·m | 0.138255 | 7.23302 |
The ft·lb → kgf·m row is the product of the two primary constants (9.80665 ÷ 1.35582 = 7.23302), included because older Japanese plates and newer metric manuals sit side by side in the same shop manual.
A worked example shows how little the rounding actually costs. A motorcycle manual calls for 34 N·m on an axle nut. Full precision gives 34 ÷ 1.35582 = 25.077 ft·lb; the six-figure constant quotes it 25.1 at one decimal, and even the crude mental factor 1.36 lands one notch away, at 25.0. Set the wrench to 25 and the true torque is 33.9 N·m — a tenth of a newton-metre low on a value whose wrench tolerance is ±1 N·m or more. The digits that matter live in the source spec, not in the seventh decimal of the constant.
Torque is force times lever arm, so every torque unit is a force unit welded to a length unit. The imperial side grew out of the workshop: American machinists thought in feet and inches, so large fasteners were specified in foot-pounds and small ones in inch-pounds, with the split sitting near one foot-pound — below it, a foot-pound dial would be too coarse to set meaningfully, so the scale switched to twelfths. The metric side did the same thing more tidily: the newton-metre carried everything from camera tripod heads (single-digit N·m) to truck axle nuts (hundreds), because SI prefixes absorb the range instead of new units.
Neither system is more "correct"; they diverged for institutional reasons. United States customary units survived in US manufacturing, and SAE and ASME fastener literature was written around them. SI, promoted through documents like NIST SP 811, became the language of international engineering trade, and German and Japanese industry standardized on it early — which is why DIN and JIS torque tables speak N·m natively.
The automotive industry forced the convergence. Engines and components crossed oceans as complete designs: a Japanese engine assembled in an American plant, serviced by American technicians, carries JIS torque values printed in N·m onto a vehicle whose every other label reads in pounds. Manufacturers responded by dual-printing — spec plates, service manuals, and eventually wrench dials carried both scales. By the 1990s, US-market tools routinely shipped with an ft·lb primary scale and an N·m (or in·lb) secondary scale, and today a torque spec without a metric value is the exception.
The practical residue is the situation this converter exists for: two documentation traditions, one joint. The memorable anchor is 1 N·m ≈ 0.74 ft·lb, so metric values run about three-quarters of their foot-pound equivalents — 100 N·m is roughly 74 ft·lb. Reverse it and 1 ft·lb ≈ 1.36 N·m. Neither shortcut replaces the table or the calculator, but each will catch the most common error, which is applying the factor in the wrong direction and being off by roughly a third.
One torque, four ways to write itPhoto: UnsplashNotation, briefly: ft·lb and lb·ft are the same unit — engineering references put the distance first, torque-wrench dials and much automotive copy write it second. N·m is sometimes written Nm or Nm³-free as plain "NM" on cheap dials; kgf·m survives mainly on legacy Japanese plates. This page sticks to the dot notation in the heading because it makes the force-length structure of the unit visible.
A click-type wrench does exactly one thing: it releases at the torque its adjustment is set to, in whatever unit its scale is printed in. The wrench has no opinion about the manual in your other hand. Almost every unit-related fastener failure traces to the gap between those two documents — and the gap widens when the scale is a small drum with two rows of numbers, or when the spec was converted by someone in a hurry.
The arithmetic of the classic mistakes is worth seeing once, because the sizes are shocking. Setting "25" for a 25 N·m spec on a wrench whose scale reads foot-pounds does not miss by a little: 25 ft·lb is 33.9 N·m, about 36% over specification. On an M8 class 8.8 bolt, whose useful band before yield sits not far above that, a 36% overshoot is the difference between a correctly preloaded joint and a stud that yields during installation. The reverse miss is quieter: setting 25 on an inch-pound wrench for a 25 N·m spec tightens to 2.8 N·m, a joint that will back off the first week. The middle case is the nastiest — a dual-scale drum where the ft·lb scale runs the outer edge and the N·m scale the inner row, and the lock collar hides the row you are reading.
33.9 N·m delivered — about 36% over spec. Common on M8-size work, where the margin to yield is thin. The wrench feels normal; the bolt is already stretched.
A 12× error in one direction or the other. 96 in·lb typed into a foot-pound dial becomes 96 ft·lb — twelve times the intent — while the converse leaves the joint barely finger-snug.
Dual-scale drums differ between rows by the conversion factor itself, so a one-row slip reproduces a full ft·lb ↔ N·m or ft·lb ↔ in·lb mistake with the wrench nominally 'correct'.
The defenses are procedural, not heroic. Convert once, before you pick up the wrench, and write the target on the work order — never convert at the wrench with the drum half-locked. Name the unit out loud when setting: "forty newton-metres" against a scale that visibly says FT·LB forces the mismatch into the open. Verify the lock collar is seated before pulling, because a dragging adjustment can click early at any unit. And when the spec and the scale cannot be reconciled — an in·lb-only wrench against a large fastener, or an ft·lb dial against a small one — swap tools rather than rescale; the wrench range was chosen so its middle third is where accuracy lives, and a forced rescale pushes the setting to the end of the drum where click accuracy is worst.
The inch-pound is not a curiosity left over from history — it is the resolution unit of small-bolt work. A click wrench is only accurate across a useful band of its scale (middle third is the working answer), so a wrench that spans 10–150 ft·lb cannot honestly deliver a click at 1 ft·lb, let alone the 0.5 ft·lb a valve-cover bolt needs. Manufacturers solved this with a smaller tool: 1/4-inch and 3/8-inch drive click wrenches graduated 20–200 in·lb, which is 1.7–16.7 ft·lb — exactly the range where small fasteners live. The inch-pound scale exists because the foot-pound scale cannot subdivide finely enough down there.
The conversion asymmetry is what makes mixed-unit work on small fasteners error-prone. Small specs in metric manuals run 2–10 N·m, which becomes large numbers in inch-pounds: 5 N·m is 44.3 in·lb, 8 N·m is 70.8 in·lb, 10 N·m is 88.5 in·lb. And the famous ratio in this family — twelve — sits ready to be grabbed for the wrong pair: a technician who converts 8 N·m to inch-pounds by multiplying by 12 delivers 96 in·lb, which is 10.85 N·m — a 36% overshoot on a fastener that was specified carefully low to protect plastic housing threads. Where the joint is plastic into metal, the stripping happens at installation; where it is metal into metal, the loss shows up later as a warped housing or a leaking seal.
Typical inch-pound territory, in the sense of what the unit is routinely asked to express: electrical and electronics assembly in the 10–40 in·lb band, small-engine covers and carburetor flanges in the 60–120 in·lb band, plumbing fixture bolts and transmission pans in the 80–150 in·lb band, and bicycle component specs that increasingly quote N·m but are executed on inch-pound or N·m 1/4-inch-drive wrenches. If your wrench is inch-pound and the manual is metric, multiply the N·m value by 8.85073 once, write it down, and treat the inch-pound number as the spec from then on — re-deriving it at the bench is exactly the failure mode described above.
One more reason the unit persists on the imperial side: fastener size. The #10, 1/4-inch, and 5/16-inch hardware that dominates US light assembly is designed around joint strengths that metric manuals would express as 4–12 N·m — and 4–12 N·m translates to 35–106 in·lb, numbers an inch-pound wrench sets directly and honestly. The unit is not legacy; it is the right graduation for the hardware, and the converter above keeps it one keystroke away from the metric manuals that increasingly specify the same joints.
Before SI torque became the default, Japanese industry — like much of the pre-war metric world — specified torque in kilogram-force metres, written kgf·m (or often just kg·m on plates and in older manuals). The unit is intuitive to anyone who has hung a weight on a wrench handle: one kgf·m is one kilogram of force pulling at one metre of lever, the everyday "hang a 10 kg weight a metre out" mental model of a torque wrench. The definition is exact — the kilogram-force was fixed at 9.80665 N by the 3rd CGPM in 1901 — so 1 kgf·m = 9.80665 N·m precisely, with no measurement uncertainty anywhere in the conversion.
The unit was retired from new standards for a good reason: kgf quietly confusing mass with force is exactly the failure SI was designed to eliminate. You cannot plug a kilogram-force into Newton’s second law without remembering g, and documents from NIST SP 811 downward classify it as a deprecated unit to be phased out of technical use. Japanese service literature made the transition decades ago, so modern manuals speak N·m. But vintage motorcycles, classics, and equipment with long production runs still circulate with plates and manual pages quoting kgf·m, and used-market documentation gets photocopied forward for decades.
Converting from a plate is a two-step habit worth automating with a mental anchor: kgf·m × 9.80665 gives N·m, so a typical passenger-car wheel-lug figure of 11 kgf·m is 107.9 N·m, which is 79.6 ft·lb — squarely inside the 100–120 N·m band modern lug specs occupy, a useful sanity check that the conversion landed in the right neighborhood. Two other anchors cover most bench needs: 1 kgf·m ≈ 9.81 N·m (so metric specs divided by roughly ten recover the old plate value), and 1 kgf·m = 7.233 ft·lb for direct old-plate to US-wrench conversion. The kgf·m column in the quick chart above exists precisely so a legacy plate and a modern manual can be compared without any arithmetic at all.
One caution when a kgf·m value is all you have: plates stamped decades ago describe joints designed to the metallurgy and gasket technology of their era, and a converted torque does not certify a modern substitution. Treat a converted kgf·m figure as historical documentation — accurate to reproduce the original assembly, insufficient to justify fitting a different bolt grade, a new gasket type, or a repaired thread without engineering review.
These are the values that cross unit systems most often in real shop work, shown with all four conversions computed from the page constants. The applications are indicative only — they describe where such values typically occur, not what any specific joint requires. The number that governs your fastener is the one in its service manual, drawing, or standard; a converted value never overrides it.
Small-fastener territory: plastic trim fasteners, electronics brackets, small-engine covers, bicycle cockpit components. The inch-pound figure is the useful one here — this is 1/4-inch-drive wrench country, where an ft·lb dial would be reading its bottom, least-accurate end.
A workhorse value around M8 class 8.8 hardware and mid-size brackets. This is also the number behind the classic field error in the section above: read in the wrong unit, 25 becomes 33.9 N·m — a 36% overshoot that a class 8.8 M8 bolt cannot absorb.
Spark-plug territory on many engines (typical plugs sit in the 20–30 N·m band depending on seat and thread), plus M10 light brackets. Cross-thread risk makes the conversion habit matter here: overtightening a plug in an aluminum head is an extraction job, not a re-torque.
Around typical M10 class 8.8 assemblies — engine-mount brackets, medium hose flanges, suspension light hardware. Both ft·lb and in·lb wrenches can serve this value, which is exactly why it gets set on the wrong scale: the number is plausible in every unit.
M12 class 8.8 territory: subframe light fasteners, larger brackets, flange bolts on process equipment. At this level the 3/8-inch-drive ft·lb wrench is the natural tool, and the in·lb figure (531) should read as a red flag — no inch-pound wrench spans it honestly.
Wheel-lug territory: typical passenger-car lug specs cluster in the 100–120 N·m band, and legacy Japanese plates quote the same joints around 10–12 kgf·m. Impact-then-click practice makes the ft·lb figure the one most often needed, and the kgf·m figure the one most often rediscovered from an old plate.
Every value above is generated by the same NM_PER constants the converter uses; changing a constant in the code would move the table, the chart, the FAQ, and these cards together, so the page cannot contradict itself.
Start from the accuracy of the tool, because no conversion can be better than the wrench that applies it. Hand torque tools are governed by ISO 6789-1:2017, which for Class A click-type wrenches permits a maximum relative deviation of ±4% over the tool’s working range — and individual wrenches in service, uncalibrated for years, drift beyond that. A ±4% band around a 100 N·m spec is ±4 N·m. Against that, the rounding this page applies is invisible: one decimal of ft·lb is 0.14 N·m, about 0.14% of the value — roughly a thirtieth of the wrench’s own tolerance.
That comparison gives a simple quoting rule: one decimal place for ft·lb values, one for N·m at bench precision, and inch-pound values to the nearest whole pound (the 12:1 ratio means whole inch-pounds are a finer resolution than tenths of a foot-pound). The tables on this page follow exactly that rule. Two decimals earn their place only where the number itself is the deliverable — a documented calibration procedure, a test report, or a factor table like the one above — and never at the wrench, where a drum cannot be set to them anyway.
The one place rounding genuinely bites is the round trip. Convert 73.8 ft·lb back to metric and you get 100.01 N·m — harmless. But convert, round to a whole number, convert back, and round again at every step, and errors accumulate: 73.756 → 74 ft·lb → 100.3 N·m → 100 N·m still looks fine here, yet the same chain applied to a small value — 5.9 ft·lb → 6 → 8.13 N·m — has drifted 1.7% from the 8 N·m you started with, purely from digits. The fix is procedural: convert once in the correct direction, round to the quoting rule, and stop. Never re-derive a target that has already been written down.
Direction checks are the final guard. Because 1 N·m ≈ 0.74 ft·lb, a correct metric-to-imperial conversion always makes the number a bit smaller; because 1 ft·lb ≈ 1.36 N·m and 1 N·m ≈ 8.85 in·lb, imperial-to-metric and metric-to-inch conversions make it larger. If your result moved the wrong way, or barely moved at all when converting between distinct units, stop and check which factor you used — the magnitude error from an inverted factor is 36% or more, and on a torque spec that is the difference between a preloaded joint and a broken one.
This converter answers what does the number say; the torque ↔ clamping-force calculator on the homepage answers what does the number do — enter the bolt, its grade and the friction conditions, and it computes the wrench torque and the preload the joint actually receives, in your choice of units. When the conversion is done and you want the rest of the toolset — length, shear, sizing, engagement — the bolt calculators hub collects them in one place, built on the same published constants so no two tools on this site disagree about what a foot-pound is.
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