Horsepower Calculator

Calculate horsepower from torque and RPM, or estimate HP from vehicle weight and quarter-mile time. Get BHP, WHP, and metric horsepower conversions.

Brake Horsepower (BHP)

300.0 HP

Metric HP (PS/CV)

304.2 PS

Wheel HP (WHP)

246.0 HP

Electrical HP

300.1 HP(e)

WHP estimated with RWD drivetrain loss (18%).

Power-to-weight: 0.09 HP/lb |  0.14 W/kg

Understanding the Horsepower Formula

James Watt defined 1 horsepower as the power needed to lift 33,000 pounds one foot in one minute. The modern formula for calculating horsepower from torque is: HP = (Torque × RPM) ÷ 5,252. The constant 5,252 comes from the math: 33,000 ft-lb/min ÷ 2π = 5,252. This means that at 5,252 RPM, torque and horsepower are always equal. Below 5,252 RPM, torque is higher; above it, horsepower is higher.

Typical Horsepower Ranges

  • Compact Car: 100-200 HP
  • Family Sedan: 180-300 HP
  • Sports Car: 300-500 HP
  • Supercar: 500-800 HP
  • Hypercar: 800-2,000+ HP
  • Motorcycle: 50-200 HP

Frequently Asked Questions

What is horsepower and how is it calculated?
Horsepower measures the rate at which an engine does work. The basic formula is: HP = (Torque × RPM) ÷ 5,252. This means horsepower is always a function of both torque and engine speed. An engine that produces 300 lb-ft of torque at 5,252 RPM makes exactly 300 HP. The 5,252 constant comes from James Watt's original definition of horsepower (33,000 ft-lb/min ÷ 2π).
What's the difference between horsepower and torque?
Torque is a twisting force measured in lb-ft or Nm — it's what you feel when you accelerate. Horsepower is the rate at which that torque is delivered over time. Think of torque as how hard you can push, and horsepower as how fast you can push it. Diesels typically have high torque at low RPM for towing, while sports cars have high horsepower at high RPM for speed.
How do I estimate horsepower from quarter-mile time?
A common formula to estimate horsepower from quarter-mile time and vehicle weight is: HP = (Weight in lbs ÷ (ET ÷ 5.825)³). For example, a 3,500 lb car running a 14-second quarter-mile has approximately: 3500 ÷ (14 ÷ 5.825)³ ≈ 252 HP. This is a rough estimate that assumes good traction and optimal gearing.
What's the difference between BHP, WHP, and HP?
BHP (Brake Horsepower) is the engine's output measured at the crankshaft before drivetrain losses. WHP (Wheel Horsepower) is the power actually measured at the wheels after losses through the transmission, differential, and axles. Typical drivetrain loss is 10-15% for front-wheel drive, 15-20% for rear-wheel drive, and 20-25% for all-wheel drive. Most manufacturer ratings are BHP.
How does altitude affect horsepower?
At higher altitudes, air is less dense, which means less oxygen for combustion. Naturally aspirated engines lose about 3% of their power for every 1,000 feet above sea level. At 5,000 feet, a 300 HP engine would produce only about 255 HP. Turbocharged and supercharged engines are much less affected because they compress the air before feeding it to the engine.
What modifications add the most horsepower?
The most cost-effective horsepower upgrades are: ECU tuning/reprogramming ($300-600 for 15-40 HP), cold air intake ($200-400 for 5-15 HP), exhaust system ($500-1,200 for 10-20 HP), and turbocharger/supercharger kits ($3,000-7,000 for 50-150+ HP). Always consider that major power upgrades may require supporting modifications like fuel system, cooling, and drivetrain upgrades.

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