Quarter-mile ET & trap speed calculator

Estimate a car's quarter-mile elapsed time and trap speed from horsepower and race weight, using the classic formulas ET = 5.825 × (weight ÷ HP)^⅓ and mph = 234 × (HP ÷ weight)^⅓.

Horsepower Race weight (with driver)

—seconds (1/4 mile)
—trap speed

Read this before you trust it

These formulas assume good traction and a typical launch. All-wheel-drive cars and EVs usually beat the ET estimate because they launch better; rear-drive cars on street tyres often miss it. The trap-speed estimate is usually closer than the ET.

The way to know is to measure: Holeshot times the real 1/4 mile, trap speed included.

Holeshot: 0-60 & 0-100 Timer

Motion sensors + GPS at 100 Hz. Every split, every run, hands-free.

Coming soon on iPhone