Engine power from torque
Type the torque and the engine speed (revolutions per minute) at the same moment: you get the power in kW and horsepower.
Result
125.66 kWPower
- In metric horsepower (PS)
- 170.9
- In horsepower (hp)
- 168.5
- Torque in lb·ft
- 295 lb·ft
Inputs
- Torque
- 400
- Torque unit
- N·m
- Engine speed
- 3000
How it is calculated
P (kW) = torque (N·m) × speed (rpm) ÷ 9,549.
Result
Power
- In metric horsepower (PS)
- 170.9
- In horsepower (hp)
- 168.5
- Torque in lb·ft
- 295 lb·ft
How it is calculated
- P (kW) = torque (N·m) × speed (rpm) ÷ 9,549.
- 9,549 comes from 60,000 ÷ 2π.
- 1 PS = 0.7355 kW; 1 hp = 0.7457 kW; 1 lb·ft = 1.3558 N·m.
Example
400 N·m at 3,000 rpm: 400 × 3,000 ÷ 9,549 ≈ 125.7 kW, about 171 PS.
Good to know
- This is a physical measurement: torque and speed must be read at the same moment.
- Peak torque and peak power do not happen at the same engine speed.
- This is not an empirical estimate (weight, acceleration): those are much less precise.
Frequently asked questions
What is this tool used for?
Type the torque and the engine speed (revolutions per minute) at the same moment: you get the power in kW and horsepower.
How is the result calculated?
P (kW) = torque (N·m) × speed (rpm) ÷ 9,549.
What should I check before using the result?
This is a physical measurement: torque and speed must be read at the same moment.