Torque to HP Calculator

Convert torque (ft-lb or Nm) to horsepower at a given RPM. Uses the standard formula: HP = (Torque × RPM) ÷ 5252.

Torque Input

RPM

Peak HP typically occurs at higher RPM

Horsepower Result

300 ft-lb @ 5000 RPM = 285.61 HP

Formula: HP = (Torque × RPM) ÷ 5252

About the Constant 5252

The constant 5252 comes from: 33,000 ft-lb per minute ÷ (2π) = 5252. This is where one horsepower equals one ft-lb of torque.

Torque to HP Reference Chart

Torque (ft-lb) @ 3000 RPM @ 5000 RPM @ 6000 RPM @ 7000 RPM
100 ft-lb 57 HP 95 HP 114 HP 133 HP
200 ft-lb 114 HP 190 HP 229 HP 267 HP
300 ft-lb 171 HP 286 HP 343 HP 400 HP
400 ft-lb 229 HP 381 HP 457 HP 533 HP
500 ft-lb 286 HP 476 HP 571 HP 667 HP

Torque to HP Calculator - Understanding Power and Torque

The Torque to HP Calculator uses the fundamental relationship between torque, rotational speed (RPM), and power to calculate horsepower. This relationship is essential for understanding engine performance, motor sizing, and mechanical system design.

The Power Equation

The relationship between torque and horsepower is defined by the equation:

  • For lb-ft: HP = (Torque × RPM) ÷ 5,252
  • For Nm: HP = (Torque × RPM) ÷ 7,121
  • Note: 5,252 and 7,121 are conversion constants

Understanding Torque vs. Horsepower

Torque and horsepower measure different aspects of rotational power:

  • Torque: Measures rotational force or "twisting power" - how much force is applied
  • Horsepower: Measures the rate of work - how quickly that force is applied
  • RPM: The speed at which the rotation occurs
  • Key Relationship: At 5,252 RPM, torque and HP are numerically equal

How to Use This Calculator

  • Step 1: Select your preferred torque unit (lb-ft, Nm, etc.)
  • Step 2: Choose calculation direction (Torque→HP or HP→Torque)
  • Step 3: Enter torque and RPM values (or HP and RPM)
  • Step 4: Click calculate to see the result with the mathematical formula

Real-World Applications

  • Automotive: Understanding engine power curves and performance characteristics
  • Electric Motors: Sizing motors for specific torque and speed requirements
  • Industrial Equipment: Calculating power requirements for machinery
  • Engineering Design: Optimizing gear ratios and power transmission systems