Torque Converter - N·m, ft·lbf, in·lbf & More

Common torque conversions

How torque conversion works

All conversions pass through Newton-metres (N·m), the SI unit of torque. Torque is the rotational equivalent of linear force: τ = r × F, where r is the lever arm length.

Note: 1 ft·lbf = 12 in·lbf exactly. Inch-ounces (in·ozf) are 1/16 of inch-pounds.

What is torque?

Torque (τ) is a rotational force - the tendency of a force to rotate an object about an axis. The formula is:

τ = r × F

Where r is the length of the lever arm (in metres) and F is the applied force (in Newtons). A 1-metre wrench with 100 N of force applied at right angles to the handle produces exactly 100 N·m of torque. A 0.5-metre wrench with the same force produces 50 N·m.

Torque differs from power. Power (watts) = torque (N·m) × angular velocity (rad/s). An engine can produce high torque at low RPM or high power at high RPM - these are related but distinct quantities.

Automotive context

Engine specifications list both peak torque and peak power, which typically occur at different RPMs:

• Diesel engines: high torque at low RPM (1,500–2,500 RPM). This makes them well-suited for towing, hauling, and acceleration from low speeds.
• Petrol / gasoline engines: peak power typically at higher RPM (5,000–7,000 RPM). The power band is narrower; requires more gear changes to stay in the optimal range.
• Electric motors: maximum torque available from 0 RPM. This is why electric vehicles feel extremely responsive from a standing start.

Torque wrench accuracy note

Click-type torque wrenches (the most common type) have a tolerance of approximately ±4% at full scale according to ISO 6789. In practice, this means:

• A setting of 80 N·m may apply anywhere from 76.8 N·m to 83.2 N·m.
• Always calibrate in the direction of use (clockwise for right-hand threads).
• Store wrenches at their minimum torque setting to preserve the spring.
• Re-calibrate after any impact or drop.