Moment of Force Converter
Convert between N·m, lbf·ft, lbf·in, kgf·m, dyn·cm, and other torque units.
Moment of Force Converter
Enter a moment of force (torque) and select its unit — all other units update instantly.
Why Lever Arm Length Matters — τ = F × r
Same force, different lever arms:
Moment of force (torque) = Force × Perpendicular distance from the axis. Doubling the lever arm doubles the torque — unlike moment of inertia where distance is squared.
Common Moment of Force Values
How to Convert Between N·m, Lbf·Ft, and Kgf·Cm
Your torque wrench is calibrated in lbf·ft, but the engine manual specifies 110 N·m for the cylinder head bolts. Type 110, select N·m, and see that it equals 81.13 lbf·ft, 11,217 kgf·cm, and 973 lbf·in. The wrench diagram shows the linear relationship between lever arm length and torque.
The converter handles 14 units: N·m, kN·m, mN·m, cN·m, μN·m, lbf·ft, lbf·in, oz·in, kgf·m, kgf·cm, gf·cm, gf·m, dyn·cm, and dyn·m. A mechanic tightening wheel nuts at 100 lbf·ft sees it equals 135.6 N·m. A physicist measuring 2,500 dyn·cm from a torsion balance sees it equals 0.00025 N·m. The material reference covers torque values from smartphone vibration motors to Formula 1 engines.
Why N·m and Joules are not interchangeable
Both have dimensions of kg·m²/s², but torque is a vector (force x distance) and energy is a scalar (work done). A motor producing 100 N·m does not produce 100 J unless it rotates through 1 radian. Energy = torque x angle in radians. Using N·m when you mean J (or vice versa) produces wrong results in power calculations.
A mechanic using a 0.25 m wrench with 200 N force gets 50 N·m. Switching to a 0.5 m wrench doubles the torque to 100 N·m with the same force. This is why breaker bars and cheater pipes exist: they increase the lever arm. The wrench diagram on this page demonstrates this linear relationship.
Under-torqued lug nuts can vibrate loose. Over-torqued nuts can strip threads or crack the wheel hub. A typical car requires 80-110 N·m (60-80 lbf·ft). A truck requires 300-600 N·m. If you use a wrench calibrated in lbf·ft but read the N·m specification without converting, you under-torque by 36% (since 1 lbf·ft = 1.356 N·m).
How the Moment of Force Converter Handles N·m and Lbf·Ft
All conversions pass through Newton-meters (N·m). When you enter 100 lbf·ft, the tool multiplies by 1.35582 to get 135.58 N·m. Then it divides by each target unit's factor: by 1,000 for kN·m, by 0.09807 for kgf·cm, by 0.11298 for lbf·in. The result: 100 lbf·ft = 135.58 N·m = 1,627 lbf·in = 13,826 kgf·cm.
The lbf·ft factor of 1.35582 comes from two exact definitions
1 lbf·ft = 1 lbf x 1 ft = 4.44822 N x 0.3048 m = 1.35582 N·m. The lbf (pound-force) is defined as the force on 1 pound mass in standard gravity: 1 lbf = 0.45359237 kg x 9.80665 m/s² = 4.44822 N. The foot is exactly 0.3048 m. Multiplying gives 1.35582 N·m exactly.
Why kgf·cm is still common in Asian manufacturing
1 kgf·cm = 0.0980665 N·m (since 1 kgf = 9.80665 N and 1 cm = 0.01 m). Japanese and Chinese motor datasheets often specify torque in kgf·cm because it relates directly to the force a 1 kg mass exerts at 1 cm lever arm. A servo motor rated at 50 kgf·cm produces 4.903 N·m. Converting to N·m: 50 x 0.09807 = 4.903 N·m. Converting to lbf·ft: 4.903 / 1.35582 = 3.62 lbf·ft.
The dynamic formatting handles the full range from micronewton-meters (MEMS devices, 10^-9 N·m) to kilonewton-meters (heavy machinery, 10^5 N·m). Very small values use scientific notation. Very large values use locale-formatted numbers. The converter also handles dyne-centimeters (CGS, 10^-7 N·m) for physics lab work with torsion balances.
Frequently Asked Questions
How do I convert 100 lbf·ft to N·m?
Multiply by 1.35582: 100 x 1.35582 = 135.58 N·m. For a quick estimate, multiply by 1.36: 100 x 1.36 = 136 N·m. The reverse: divide by 1.35582 or multiply by 0.7376. So 200 N·m = 147.5 lbf·ft. The converter shows all 14 units simultaneously.
What is the torque of a car engine?
A typical gasoline engine produces 100-300 N·m (74-221 lbf·ft). A diesel engine produces 250-600 N·m (184-443 lbf·ft) because diesel combustion creates higher cylinder pressure. A Formula 1 engine produces about 450 N·m (332 lbf·ft) but at 15,000 RPM. A motorcycle produces 50-200 N·m at much higher RPM.
Why are N·m and Joules different if they look the same?
N·m is torque: force x distance (a vector). J is energy: work done (a scalar). A motor producing 100 N·m does 100 J of work only if it rotates through 1 radian (57.3 degrees). Through a full revolution (2π radians), it does 628 J. Using N·m when you mean J produces wrong power calculations: P = torque x angular velocity, not P = energy x angular velocity.
How does a longer wrench help?
Torque = force x distance. Double the wrench length, double the torque for the same force. A mechanic using 200 N on a 0.25 m wrench gets 50 N·m. On a 0.5 m wrench, the same 200 N produces 100 N·m. This is why breaker bars and cheater pipes exist: they increase the lever arm. The wrench diagram on this page shows this linear relationship.
What is the torque of a smartphone vibration motor?
About 0.001 N·m (1 mN·m or 0.1 dyn·cm). This is enough to make the phone vibrate against your hand. The motor spins an eccentric mass at 10,000-20,000 RPM. The torque is tiny because the mass is small (a few grams) and the lever arm is short (a few millimetres). The converter handles this micro-torque range alongside engine-scale torque.
What is the difference between lbf·ft and lb·ft?
lbf·ft (pound-force foot) is torque: force x distance. lb·ft (pound foot) is ambiguous and sometimes used for moment of inertia (lb·ft²). Always use lbf·ft for torque to avoid confusion. The lbf (pound-force) is the force on 1 lb mass in standard gravity: 1 lbf = 4.44822 N. The converter uses lbf·ft for clarity.