To time a 0–100 km/h in a comparable way, you need a standing start, a continuous pull past 100 km/h, and a GPS already locked — not a figure from a manufacturer advert. OpenRank does this from the location points of your iPhone or Android, during a trip you start yourself.
What the manufacturer figure does not say
The 0–100 on a spec sheet comes from a protocol (mass, tyres, temperature, often launch control). It is a reference, not a verdict on your car. Load, fuel, slope and worn tyres stretch the time, sometimes by a second.
See our 0–100 km/h spec sheets for the official figure by model, then time yours.
Six-step protocol
- Legal, open road — quiet A-road, visibility, dry surface. Not a motorway in traffic, not a 30 km/h zone.
- GPS locked — take the phone outdoors, wait 20–30 s, start OpenRank recording before you stop.
- Full stop — 0 km/h, wheel straight, launch assist off if it fakes the wheelspin.
- One pull — past 110 km/h so GPS smoothing does not cut you at 99.4 km/h.
- Flat — a 2 % slope already changes the result. Avoid viaducts and downhill “for the time”.
- Repeat — three runs, same direction, drop the worst. The median beats the record.
GPS accuracy vs a wheel sensor
| Method | Typical | Limit |
|---|---|---|
| OBD / wheel sensor | ±0.05–0.1 s | Hardware, often paid |
| Dedicated GPS (10–20 Hz) | ±0.1–0.2 s | External box |
| Smartphone (OpenRank) | ±0.2–0.5 s | Urban canyons, cold GPS |
For the detail, read smartphone GPS accuracy for timing.
Common mistakes
- Starting the app as you accelerate (GPS is not stable yet).
- Launching uphill or with two passengers then comparing to the catalogue.
- Cutting at exactly 100 km/h: smoothing can show 98 km/h a second too early.
- Comparing a wet run to a summer magazine run.