Load / Torque Calculator
Calculate torque from force and radius, and power from torque and speed.
Calculator
No signup required. Results are indicative—verify for your standards.
Torque: 150.00 N·m
Power at 1000 RPM: 15.708 kW
Formula
Torque T = F × r (N·m), where F is force in Newtons and r is moment arm in metres. Power P = T × 2π × n / 60 (W), where n is speed in RPM.
Example calculation
Force 500 N at radius 0.3 m: T = 500 × 0.3 = 150 N·m. At 1000 RPM: P = 150 × 2π × 1000 / 60 ≈ 15,708 W ≈ 15.7 kW.
Engineering notes
Torque and power are linked: T = 9549 × P(kW) / RPM. Use this to verify motor selection — the motor must deliver sufficient torque at operating speed, not just adequate power.
When to use this calculator
- Shaft design — calculate torque transmitted by a shaft to size its diameter for torsional stress
- Gear drive design — determine input and output torques for gear ratio selection
- Motor selection — verify that a motor produces sufficient torque at operating RPM for the load
- Coupling selection — confirm coupling torque rating exceeds the calculated shaft torque with safety factor
- Conveyor drives — compute drive torque from belt pull and pulley radius
Frequently asked questions
- What is the difference between torque and moment?
- In everyday engineering usage, torque and moment both mean force × distance. Torque specifically refers to a twisting or rotational force about an axis (used for shafts, motors, fasteners). Moment refers to a bending or static rotational effect (used in structural beams). Both have units of N·m but they describe different physical effects.
- How do I find the torque needed to tighten a bolt?
- Bolt tightening torque T = K × d × F, where K is the nut factor (0.15–0.20 for lubricated, 0.20–0.25 for dry steel), d is bolt nominal diameter in metres, and F is the target clamp force (proof load × 70–80%). For standard fasteners, refer to torque tables in IS 1367, ASME B18.2, or the bolt manufacturer datasheet.
- How do I convert torque from kg·m to N·m?
- 1 kg·m = 9.81 N·m. Multiply the value in kg·m by 9.81 to get N·m. This conversion is important because older Indian engineering drawings often specify torque in kg·m or kgf·m, while modern standards use N·m.