Convert torque (N·m or ft·lb) and RPM to horsepower, kilowatts, and metric PS. Includes a torque×RPM power table for automotive reference.
The torque to horsepower calculator converts rotational force and speed into power using the fundamental relationship HP = Torque × RPM ÷ 5,252 (when torque is in foot-pounds). This is the most important formula in automotive engineering.
Enter torque in N·m, ft·lb, kg·m, in·lb, or in·oz, plus RPM, and get horsepower along with kilowatts, metric PS, watts, and BTU/hr. Preset buttons provide common engine scenarios from economy cars to high-performance motors.
The power table cross-references torque values from 50 to 1,000 ft·lb against RPMs from 2,000 to 6,000 — covering everything from diesel trucks to sport cars — with your current input highlighted. It helps translate dyno data into comparable power metrics for tuning, purchasing, and drivetrain planning decisions. The calculator also supports clearer communication between imperial and metric specs used by manufacturers, tuners, and motorsport documentation teams during setup, validation, and race-day adjustments across mixed toolchains. It helps avoid misreading power claims in mixed regional specs.
Engine dyno sheets report torque and RPM. This calculator converts those readings to horsepower and kilowatts — the numbers consumers and engineers use to compare vehicles and size motors more confidently across different unit systems, spec sheets, performance discussions, workshop planning tasks, and customer reports. It also speeds up consistent quote preparation.
HP = Torque (ft·lb) × RPM ÷ 5,252. kW = HP × 0.7457. PS = HP × 1.01387. In SI: Power (W) = Torque (N·m) × 2π × RPM ÷ 60.
Result: 300 ft·lb @ 5,252 RPM = 300 HP = 223.7 kW = 304.2 PS
HP = 300 × 5,252 ÷ 5,252 = 300. At 5,252 RPM, torque in ft·lb equals horsepower numerically.
Engine dyno charts plot torque and horsepower against RPM. Torque typically peaks at mid-RPM and declines at high RPM. Horsepower continues rising as long as the torque increase in RPM offsets the torque drop. The two curves cross at exactly 5,252 RPM when plotted in ft·lb and HP.
Electric motors produce peak torque at 0 RPM, giving EVs their instant acceleration. Internal combustion engines need to spin up to their torque peak. This fundamental difference explains why a 300 HP electric car can feel faster than a 400 HP gas car off the line.
When sizing electric motors, engineers calculate required torque and speed, then convert to kW for motor selection. A conveyor belt requiring 50 N·m at 1,450 RPM needs: 50 × 2π × 1,450 / 60 = 7,592 W ≈ 7.6 kW ≈ 10 HP motor.
HP = Torque (ft·lb) × RPM ÷ 5,252. You need BOTH torque and RPM — torque alone cannot be converted to horsepower.
5,252 = 33,000 ÷ (2π). It comes from the definition of 1 HP = 33,000 ft·lb per minute combined with rotational mechanics (2π radians per revolution).
Because the formula HP = T × RPM / 5,252 equals T when RPM = 5,252. This is a mathematical identity, not a physical law.
HP (mechanical horsepower) = 745.7 watts. PS (Pferdestärke, metric horsepower) = 735.5 watts. PS is ~1.4% more than HP.
Yes: HP = N·m × RPM ÷ 7,127 (since 5,252 × 1.35582 ≈ 7,121, but use exact: P(kW) = T(N·m) × RPM ÷ 9,549).
Torque is rotational force (how hard the engine pushes). Horsepower is power (how fast it can do work). Torque accelerates, horsepower determines top speed.