HP & Torque Calculator
Solve HP, torque, and RPM — convert speed units and estimate 0–60 and quarter-mile
Horsepower, torque, and RPM are connected by one precise formula: HP = Torque × RPM ÷ 5,252. Enter any two values and our calculator solves for the third instantly. It's the same math engineers use — perfect for evaluating spec sheets or understanding what a performance modification actually does.
The Performance tab goes further: enter your HP and vehicle weight for estimated 0–60 mph and quarter-mile times based on power-to-weight ratio. These estimates are surprisingly accurate for stock vehicles and an excellent way to compare cars before a test drive.
How to Use the HP & Torque Calculator
- 1 On the HP ↔ Torque tab, enter any two of the three values and click the solve button for the unknown.
- 2 On the Speed Convert tab, type in any field (MPH, KPH, or m/s) — the others update automatically.
- 3 On the Performance tab, enter your car's horsepower and curb weight in lbs, then click Estimate Performance.
- 4 Results show estimated 0–60 mph time and quarter-mile ET with a real-world variability note.
Peak torque on spec sheets is measured at a specific RPM — that's the only point where the formula is exact. At any other RPM, the torque value changes. Peak HP and peak torque don't occur at the same RPM for most engines.
Frequently Asked Questions
What is the difference between horsepower and torque?
Torque is the rotational force your engine produces — it's what you feel when you floor the throttle from a stop. Horsepower is torque multiplied by RPM (over time) — it determines top speed and sustained acceleration. High torque = great off-the-line pull; high HP = fast at speed.
Why does HP = Torque × RPM / 5252?
The constant 5,252 comes from the definition of one horsepower (550 ft-lbs/sec) divided by 2π (to convert rotations to radians) × 60 seconds. It's why HP and torque values always equal each other numerically at exactly 5,252 RPM on any dyno chart.
How accurate is the 0–60 estimate?
The estimate is based on power-to-weight ratio and is typically within 0.5–1 second for stock, rear-wheel-drive vehicles on a dry surface. FWD cars often underperform due to torque steer; AWD cars often beat the estimate due to superior traction from launch.
What is considered a good power-to-weight ratio?
Reference points: 0.05 HP/lb (20 lb/HP) is sporty; 0.1 HP/lb approaches supercar territory. A typical family sedan runs 0.05–0.07 HP/lb. Formula 1 cars exceed 0.7 HP/lb. Most enthusiasts target at least 0.05 HP/lb — 200 HP in a 4,000 lb car.