Torque Unit Converter
Torque is the rotational analogue of force — the "twist" applied around an axis. It shows up everywhere from cars and bicycles to electronics assembly and physics lab work, but every region and industry uses different units. Enter any one value and this tool instantly shows it in all 11 of the common torque units side-by-side: SI (N·m, kN·m, N·cm, mN·m), international engineering (kgf·m, kgf·cm, gf·cm), US customary (lbf·ft, lbf·in, ozf·in) and CGS (dyn·cm). Every factor is derived from the exact BIPM / ISO 80000 and NIST SP 811 definitions — no rounded conversion-factor drift.
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Live value in every torque unit
Tip: 1 N·m ≈ 0.7376 lbf·ft = 8.851 lbf·in ≈ 10.20 kgf·cm. Typical car lug-nut torque is 90–140 N·m; common bicycle bolts are 5–10 N·m.
- N·m SI standard — automotive, mechanical, engineering
- lbf·ft US torque wrenches, car service manuals
- lbf·in Bicycles, small fasteners, hardware-store drivers
- kgf·cm JP/KR bicycles, motorcycles, household wrenches
- ozf·in Precision tools, electronics, micro-motors
- dyn·cm Physics / CGS unit (1 dyn·cm = 1 erg)
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Formula
Every unit is first converted into newton-metres (N·m) and then divided by the target unit’s newton-metre-equivalent.
- · 1 lbf·ft = 1.355 817 948 33… N·m — derived exactly from 1 lbf = 4.448 221 615 260 5 N and 1 ft = 0.3048 m.
- · 1 lbf·ft = 12 lbf·in = 192 ozf·in. ozf·in is widely used for precision electronics.
- · 1 kgf·m = 9.806 65 N·m exactly (ISO 80000-4); 1 kgf·cm = 0.098 066 5 N·m.
- · 1 N·m ≈ 0.737 562 149 lbf·ft = 8.850 745 79 lbf·in ≈ 10.197 2 kgf·cm — the cross-checks worth memorising.
- · 1 dyn·cm = 1e-7 N·m = 1 erg; the CGS unit still appears in older physics problems.
- · Negative values are accepted for reverse-rotation or pre-load wrenches.
- · Common references: passenger-car lug nuts 90–140 N·m, light trucks 130–200 N·m, bicycle bolts 5–10 N·m.
- · Sources: NIST SP 811 App. B (2008 ed.), BIPM SI Brochure 9th ed., ISO 80000-4 (Mechanics).
Frequently asked
My car manual says "torque the lug nuts to 110 N·m" but my torque wrench only reads in lbf·ft — what should I set it to?
Divide 110 by 1.355 817 948 — you get about 81.1 lbf·ft. Most home torque wrenches have a scale that reaches 80–100 lbf·ft, so set the click point to 81 and tighten until it clicks. Pro tip: tighten in a criss-cross pattern in two or three passes, only reaching the final torque on the last pass, to avoid pulling the wheel hub off-centre.
lbf·ft, ft·lbf, ft-lb — are these all the same?
They are different spellings of the same unit. Physics convention writes it "pound-force × foot" — hence lbf·ft — but industrial practice often reverses it to ft·lbf or ft-lb. The numeric value is identical. Do not confuse it with the foot-pound of energy (1.356 J), which is dimensionally different even though the magnitudes match: torque measures twist, energy measures work done.
Why is kgf·cm so common on Japanese and Korean bicycles and motorcycles?
Japan and Korea kept the older "MKS gravitational" engineering tradition, treating the kilogram-force as a practical unit of force. Consumer torque wrenches and service manuals therefore stayed in kgf·m / kgf·cm even after the SI N·m became the international standard. A useful shortcut: 1 N·m ≈ 10.2 kgf·cm, so multiplying a newton-metre reading by 10 gets you close to kgf·cm.
Can my torque wrench measure as low as 5 N·m? Is that even practical for bicycle bolts?
5 N·m is at the low end of most household torque wrenches. You will get much better accuracy with a dedicated low-range driver covering 2–24 N·m (or 20–200 kgf·cm); large lug-nut wrenches can be off by ±20 % at the bottom of their range. Carbon-fibre handlebars, seatposts and brake clamps typically call for 5 N·m or less, and pre-set "click and stop" drivers fixed at 5 N·m are popular for periodic bicycle maintenance.
Why does the calculator accept a negative value like -25 N·m?
Torque is a vector quantity — direction (clockwise vs. anticlockwise) matters. Pre-load calculations, reverse-torque measurements and loosening-torque specifications all use signed values, so we preserve the sign instead of taking the absolute value. If you only care about the magnitude of how hard to twist, just ignore the negative sign.
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