RaceBuddy

Drag racing
slope calculator.

Enter your run distance and the height difference between start and finish. The calculator returns slope angle, grade, the gravity-along-slope acceleration correction, and an estimated time impact at quarter-mile distance.

Calculator

Slope angle
0.1424°
Grade
0.249%
Accel correction
0.0244m/s²
g · sin(angle) — added to a downhill measurement, subtracted from an uphill one.
Δt at 1/4 mile
+0.017s
Estimate at a₀ = 7.5 m/s². Actual impact varies with the car.
Formula · angle = asin(Δh / d) · grade = tan(angle) · accel correction = g · sin(angle)

How it works

On a sloped strip, gravity adds (downhill) or subtracts (uphill) from your measured acceleration. To compare runs taken on different surfaces, you need to remove the gravity component along the slope: g · sin(angle).

The angle comes from the height delta and the distance you measured along the ground: angle = asin(Δh / d). Grade is tan(angle) expressed as a percentage. For most strips the angle is small enough that grade ≈ Δh / d.

The Δt estimate at 1/4 mile assumes a strong street-car launch (a₀ ≈ 7.5 m/s²) and is provided as a sanity check. Real cars vary; RaceBuddy applies the acceleration correction directly to your run data.

In the app

RaceBuddy applies slope correction automatically on every drag run. See the full feature list on the Drag section.