DragMeteriPhone Air and later

Your iPhone, a performance meter.

Acceleration, distance and braking with no extra hardware. DragMeter combines GPS with the accelerometer and recalculates results more precisely after each run.

Coming to the App Store

What it measuresGPS + IMU fusion

0–100 km/halso 0–50 / 60 / 150 / 200

100–200 km/hcustom ranges

¼ mile60 ft · 1/8 · 1000 ft + trap

100–0 km/hdistance · time · deceleration

0.029 sRMS error for 0–100 km/h in simulated runs

Everything you can measure on track

For iPhone Air and later with iOS 26. Only measure on a closed track.

Acceleration

0–50, 60, 100, 150 and 200 km/h plus ranges like 60–100 or 100–200, including custom ones.

Distance

60 ft, 100 m, 1/8 mile, 1000 ft, 1/4 and 1/2 mile, always with trap speed.

Braking

100–0 km/h with stopping distance, time and deceleration.

G-meter and power

Live g-forces and a power estimate from the acceleration curve.

Track slope

The barometer tells whether you drove uphill or downhill.

History and export

Charts for every run, CSV export and a demo mode to try it out.

Sensor fusion

Precision without extra hardware.

Phone GPS alone is not enough for hundredths of a second. DragMeter fuses location with a 100 Hz accelerometer using a Kalman filter and smooths the whole run afterwards.

0–100 km/h: 0.029 s RMS
¼ mile: 0.025 s RMS

Errors come from simulated runs. Comparison with dedicated meters is still to come.