Engine Horsepower Calculator

Calculate engine horsepower, torque, or RPM using standard automotive formulas. Convert between HP, kW, PS, BHP and between lb·ft, N·m, kg·m. Free, fast, and easy to use.

Calculate

Choose a calculation type, enter your engine values, and click Calculate Now to get instant results with step-by-step solutions.

Complete User Guide

What is Engine Horsepower?

Engine horsepower measures how much power an engine produces. It is calculated from torque (rotational force) and RPM (engine speed) using the formula HP = (Torque × RPM) / 5252. This is the standard formula used for dyno testing, engine tuning, and comparing vehicle performance across different makes and models.

Core Formulas

Horsepower: HP = (Torque × RPM) / 5252

Torque: Torque = (HP × 5252) / RPM

RPM: RPM = (HP × 5252) / Torque

5 Calculation Types

Calculate Horsepower

Enter torque and RPM to get engine HP. Supports lb·ft, N·m, and kg·m torque inputs.

Calculate Torque

Enter HP and RPM to get torque output. Results in lb·ft, N·m, or kg·m.

Calculate RPM

Find the RPM at which peak power occurs for given HP and torque values.

Convert Power Units

Convert between HP, kW, PS (metric HP), and BHP.

Convert Torque Units

Convert between lb·ft, N·m, and kg·m torque units.

Supported Units

Power Units

  • HP — Mechanical Horsepower (US)
  • kW — Kilowatts (SI standard)
  • PS — Pferdestärke (Metric HP, Europe)
  • BHP — Brake Horsepower (same as HP)

Torque Units

  • lb·ft — Pound-Feet (US standard)
  • N·m — Newton-Meters (SI standard)
  • kg·m — Kilogram-Meters (metric)

Typical Engine Values

• Economy Car: 100–150 HP, 100–150 lb·ft, peaks at 4000–6000 RPM

• Sports Car: 300–500 HP, 250–400 lb·ft, peaks at 6000–8000 RPM

• Truck / SUV: 200–400 HP, 300–500 lb·ft, peaks at 3000–5000 RPM

• Supercar: 500–1000+ HP, 400–700 lb·ft, peaks at 7000–9000 RPM

Quick Examples

• 300 lb·ft at 5252 RPM → (300 × 5252) / 5252 = 300 HP

• 200 HP at 6000 RPM → (200 × 5252) / 6000 = 175.07 lb·ft

• 300 HP = 223.7 kW = 304.1 PS

• 400 N·m = 295.02 lb·ft = 40.79 kg·m

Important Notes

  • HP = (Torque × RPM) / 5252 requires torque in lb·ft. Metric inputs are converted automatically.
  • Peak HP and peak torque usually occur at different RPM values.
  • At exactly 5252 RPM, torque (lb·ft) and horsepower are numerically equal.
  • 1 HP = 0.7457 kW = 1.0139 PS. BHP is identical to HP for most purposes.

📤 Share This Tool