Engine Horsepower Calculator
Estimate engine HP from displacement and VE, calculate from quarter-mile runs, apply SAE dyno correction, and convert engine displacement units.
Engine HP Calculator
4 estimation methods
85%
Estimated Engine HP
341HP
DISPLACEMENT CONVERTER
Convert Engine Displacement Units
Cubic inches, liters, and cubic centimeters — 1L = 61.024ci = 1,000cc.
Cubic Inches (ci)
e.g. 350
Liters (L)
e.g. 350
Cubic Centimeters (cc)
e.g. 350
Use the calculator above to convert live between all three units.
ENGINE REFERENCE
Famous Engines — Displacement, HP & Torque
Iconic engines from stock cars to supercars and racing.
| Engine | Displacement | HP (SAE Net) | Torque (lb-ft) | HP/Liter | Used In |
|---|---|---|---|---|---|
| Toyota 2ZR-FXE | 1.8L | 98 HP | 105 lb-ft | 54 HP/L | Prius (hybrid) |
| Honda K20C1 VTEC Turbo | 2L | 306 HP | 295 lb-ft | 153 HP/L | Civic Type R |
| Ford 5.0L Coyote V8 | 5L | 480 HP | 415 lb-ft | 96 HP/L | Mustang GT |
| Chevy LS3 V8 | 6.2L | 430 HP | 424 lb-ft | 69 HP/L | Camaro SS, Corvette |
| Ford 5.2L Voodoo V8 | 5.2L | 526 HP | 429 lb-ft | 101 HP/L | Mustang Shelby GT350 |
| Dodge 6.2L Hellcat V8 | 6.2L | 717 HP | 656 lb-ft | 116 HP/L | Challenger/Charger SRT |
| BMW S58 Inline-6 Turbo | 3L | 503 HP | 479 lb-ft | 168 HP/L | M3 Competition |
| Ferrari F154CB V8 Turbo | 3.9L | 661 HP | 568 lb-ft | 169 HP/L | Ferrari 488 GTB |
| Bugatti W16 Quad-Turbo | 8L | 1578 HP | 1180 lb-ft | 197 HP/L | Bugatti Chiron SS |
| Chevy 427 L88 V8 | 7L | 430 HP | 460 lb-ft | 61 HP/L | 1967-69 Corvette |
💡 HP/Liter Is the Real Measure of Engine Efficiency
Comparing raw HP numbers across engines of different sizes is misleading — a big naturally-aspirated V8 and a small turbocharged four can both make 400 HP. HP-per-liter normalizes for displacement, letting you compare power density directly. Modern turbocharged engines can exceed 150-200 HP/liter, several times what a typical naturally-aspirated engine of the same size produces.
🌀 Volumetric Efficiency Explained
VE = actual air drawn in ÷ theoretical cylinder volume × 100%. Stock NA engines run 75-87%, performance-tuned NA engines can reach 100%+, and turbocharged/supercharged engines routinely achieve 110-140%+ by forcing more air into the cylinder than atmospheric pressure alone could draw.
🌡️ Dyno Correction Factors
Dyno HP readings change with ambient conditions — hot days, high altitude, and low barometric pressure mean less-dense air and lower measured HP. SAE J1349 correction normalizes all readings to 77°F (25°C), 29.92 inHg sea level. A cold winter day at sea level might apply a correction factor of ~0.90-0.95; a hot summer day at altitude could exceed 1.10-1.20.
Engine Horsepower Formulas — All Methods
Engine horsepower can be estimated through several methods, each requiring different inputs and offering a different perspective on engine performance — from a build-spec estimate before the engine ever runs, to a quarter-mile timing slip, to a corrected dyno pull.
Method 1: From Displacement, VE, and BMEP
HP = (Displacement(ci) × VE(decimal) × RPM × BMEP(psi)) / 792,000
Example: 350ci, VE=0.85, RPM=5,500, BMEP=170psi
HP = (350 × 0.85 × 5,500 × 170) / 792,000 ≈ 350 HP (estimated)Method 2: Elapsed Time (ET)
WheelHP = W × (5.825/ET)³ [W = vehicle weight in lbs, ET = 1/4-mile elapsed time in seconds]
Example: 3,400 lbs, 13.5s ET, RWD manual
WheelHP = 3,400 × (5.825/13.5)³ ≈ 296 HP (at wheels) → ≈ 326 HP (flywheel estimate, RWD)Method 3: Trap Speed
WheelHP = W × (V/234)³ [V = trap speed in mph at the 1/4-mile finish]
Example: 3,400 lbs, 105 mph trap speed, RWD manual
WheelHP = 3,400 × (105/234)³ ≈ 307 HP (at wheels) → ≈ 338 HP (flywheel estimate, RWD)SAE J1349 Dyno Correction Factor
CF = 1.18 × (990/Pd) × ((Tc+273)/298) − 0.18 [Pd = dry barometric pressure in mbar, Tc = ambient temp in °C]
Standard conditions: Pd=990mbar, Tc=25°C → CF=1.00
CorrectedHP = MeasuredHP × CF— FAQ