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Specs & ConversionsQuarter-Mile Calculator — ET & Trap Speed
Get a ballpark quarter-mile time from power and weight. Enter the car’s weight (with driver) and its horsepower for an estimated elapsed time, trap speed, and power-to-weight ratio.
How this calculator works
These use the classic Roger Huntington estimates: ET ≈ 5.825 × (weight ÷ hp)^⅓ and trap speed ≈ 234 × (hp ÷ weight)^⅓. They predict a well-driven car’s quarter-mile from power-to-weight alone, so they ignore traction, gearing, aero, and launch — real results vary, but the estimate is usually close for street cars.
What changes the number
- Use real weight including driver and fuel — every 100 lb matters at the strip.
- These formulas assume good traction and a clean launch; a car that can’t hook up will run slower.
- Wheel (not crank) horsepower gives a more realistic estimate, since that’s what reaches the ground.
Frequently asked questions
Why don’t you show 0–60?
0–60 depends heavily on launch, traction, and gearing, which makes a formula-only estimate unreliable. Quarter-mile ET and trap speed correlate far better with power-to-weight, so those are what we estimate.
How accurate is this?
For a well-sorted street car with decent traction, usually within a few tenths. Heavily modified, AWD-launched, or traction-limited cars can deviate more.
Should I use crank or wheel horsepower?
Wheel horsepower gives a more realistic number, since 10–20% of crank power is lost through the drivetrain before it reaches the tires.