Quarter Mile Calculator
Calculate drag racing ET and trap speed for 1/4 mile performance
Calculate Quarter Mile Performance
Peak engine power at the flywheel
Total weight including driver and fuel
Quarter Mile Performance
Formula Used: Fox
Speed = 230 × (P/W)^(1/3)
Performance Category
Drag Racing Physics
Elapsed Time (ET): ET = k₁ × (Weight/Power)^(1/3)
Trap Speed: Speed = k₂ × (Power/Weight)^(1/3)
Power-to-Weight Ratio: Higher ratio = better performance
Constants vary by formula: Huntington (6.290, 224), Fox (6.269, 230), Hale (5.825, 234)
Performance Analysis
Example: McLaren 720S
Vehicle Specifications
Vehicle: McLaren 720S (2018)
Weight: 1,419 kg (3,128 lbs) including driver
Power: 710 hp (529 kW)
Formula: Hale (modern, most accurate)
Calculation Steps
1. Convert to imperial: Weight = 3,128 lbs, Power = 710 hp
2. Calculate W/P ratio: 3,128 / 710 = 4.406
3. Apply Hale's ET formula: ET = 5.825 × (4.406)^(1/3) = 9.56 seconds
4. Calculate P/W ratio: 710 / 3,128 = 0.227
5. Apply speed formula: Speed = 234 × (0.227)^(1/3) = 143.8 mph
Result: ET ≈ 9.6s, Trap Speed ≈ 144 mph - Supercar level!
Famous Car Examples
Tesla Model S Plaid
Electric supercar
Dodge Challenger Hellcat
Muscle car icon
McLaren 720S
Supercar excellence
Honda Civic Type R
Hot hatch champion
Formula Comparison
Huntington (1950s)
Original empirical formula
ET: 6.290, Speed: 224
Fox (1960s)
Refined with physics theory
ET: 6.269, Speed: 230
Hale (1980s)
Modern computer-refined
ET: 5.825, Speed: 234
ET Performance Categories
< 8 seconds
Pro Stock / Funny Car
NHRA professional level
8-10 seconds
Super Stock
Highly modified vehicles
10-12 seconds
Street/Strip
Performance cars
12-14 seconds
Street Car
Sports cars
> 14 seconds
Stock Vehicle
Daily drivers
Understanding Quarter Mile Drag Racing
What is Quarter Mile Racing?
Quarter mile drag racing is a straight-line acceleration contest over exactly 1/4 mile (402.336 meters). It measures two key performance metrics: elapsed time (ET) and trap speed at the finish line.
Historical Development
The formulas evolved from Roger Huntington's 1950s empirical observations to Geoffrey Fox's 1960s physics-based refinements, and finally Patrick Hale's 1980s computer-optimized constants.
Key Physics Principles
Performance depends primarily on power-to-weight ratio. Higher power accelerates the vehicle faster, while lower weight reduces the force needed for acceleration, following Newton's second law (F = ma).
Real-World Factors
Actual performance is affected by tire grip, aerodynamics, gear ratios, driver skill, track conditions, and vehicle setup. These formulas provide baseline estimates assuming optimal conditions.
Drag Racing Applications
- • Performance car comparison
- • Modification planning
- • Competition preparation
- • Power-to-weight optimization
Engineering Uses
- • Vehicle development
- • Performance benchmarking
- • Weight reduction planning
- • Power upgrade analysis
Physics Education
- • Newton's laws demonstration
- • Power and acceleration
- • Empirical vs theoretical models
- • Real-world physics applications