Torque Calculator

Torque Guide

Torque Formula

Torque (τ) = Force (F) × perpendicular distance (d) × sin(θ), where θ is the angle between the force vector and the lever arm. When force is applied at 90° (perpendicular), sin(90°) = 1 and τ = F × d. Torque is measured in Newton-metres (N⋅m) in SI units, or foot-pounds (ft⋅lb) in imperial. 1 N⋅m = 0.7376 ft⋅lb. Torque is a vector quantity — the direction (clockwise or anticlockwise) matters for equilibrium problems.

Common Torque Values

Tightening bolts: M6 bolt ~10 N⋅m, M10 bolt ~45 N⋅m, M14 bolt ~120 N⋅m, car wheel nuts 80–130 N⋅m. Bicycle components: stem bolts 4–6 N⋅m, bottom bracket 35–50 N⋅m. Car engine output: a 1.0 litre petrol engine ~150 N⋅m, 2.0 litre diesel ~350 N⋅m, performance V8 ~700+ N⋅m. Electric motors can deliver full torque from standstill — a Tesla Model S produces ~660 N⋅m instantly. A human hand grip applies approximately 3–5 N⋅m on a standard screwdriver.

Torque Wrenches

A torque wrench ensures bolts are tightened to a specific torque, preventing over-tightening (which can strip threads or warp components) or under-tightening (which can cause fasteners to loosen). Critical applications: cylinder head bolts (often tightened in multiple stages), wheel nuts (critical for road safety), suspension components, and brake caliper bolts. Most torque wrenches specify the bolt torque in N⋅m; car manufacturer specifications are given in the service manual.

Torque and Power

Power (W) = Torque (N⋅m) × Angular velocity (rad/s). Angular velocity in rad/s = RPM × 2π/60. So Power (kW) = Torque × RPM / 9549. An engine producing 200 N⋅m at 3000 RPM generates: 200 × 3000 / 9549 = 62.8 kW (84 hp). This is why car manufacturers specify torque at a particular RPM rather than just giving a single number — torque varies across the rev range, peaking at different RPMs for petrol vs diesel engines.