Accuracy & Limitations

Expected Accuracy

Our 0 to 60 timer provides results that are typically within ±0.2-0.5 seconds of professional timing equipment under good conditions. This makes it suitable for personal performance tracking, comparing modifications, and general benchmarking.

How We Compare to Professional Equipment

What Affects Accuracy

GPS Update Rate

Phone GPS typically updates at 1-10 Hz (1-10 times per second), compared to professional GPS devices that update at 10-20 Hz. This means there can be a slight delay in detecting when you reach the target speed. Our sensor fusion approach helps compensate by using accelerometer data between GPS updates.

GPS Signal Quality

GPS accuracy depends heavily on signal quality:

• Best: Open areas with clear sky view (±3-5 meters accuracy)
• Good: Light tree cover or suburban areas (±5-10 meters)
• Poor: Urban canyons, heavy tree cover (±10-30 meters)
• Unusable: Tunnels, parking garages, indoors

Phone Mounting

Any movement of your phone during acceleration will introduce errors. A secure, rigid mount is essential. Dashboard or windshield mounts work best. Avoid cup holders, loose mounts, or holding the phone by hand.

Phone Model & Sensors

Newer phones generally have better GPS chips and more accurate sensors. Flagship phones from 2020+ typically provide the best results. Budget phones or older models may have slower GPS update rates or less accurate accelerometers.

Weather & Atmospheric Conditions

Heavy rain, storms, or atmospheric interference can degrade GPS signal quality. Clear weather provides the most consistent results.

Testing Surface

Smooth, level pavement provides the most accurate results. Rough roads, hills, or uneven surfaces can affect accelerometer readings and introduce measurement errors.

Known Limitations

GPS Lag

The most significant limitation is GPS update lag. When you reach 60 mph, there may be a 0.1-0.5 second delay before the GPS reports that speed. We use accelerometer data to estimate and compensate for this lag, but it's not perfect.

Cold Start Delay

When you first load the app or haven't used GPS recently, your phone needs time to acquire satellite locks. Wait for a strong GPS signal (indicated in the app) before starting your run.

Not Suitable for Professional Racing

This tool is designed for personal use and enthusiast-level testing. For official racing, sanctioned events, or precise engineering work, use professional timing equipment.

Quarter Mile Distance Accuracy

GPS-based distance measurements can vary by ±5-15 feet depending on signal quality. This can affect quarter mile times by 0.1-0.3 seconds. Multiple runs and averaging help mitigate this.

How to Get the Most Accurate Results

Comparing Results

Against Manufacturer Claims

Manufacturer 0-60 times are typically achieved under ideal conditions with professional drivers, optimal weather, and prepared surfaces. Real-world results are usually 0.3-1.0 seconds slower. If your times are within this range, your measurements are likely accurate.

Consistency is Key

For tracking modifications or improvements, consistency matters more than absolute accuracy. Use the same testing location, conditions, and procedures for all runs to ensure valid comparisons.

Run-to-Run Variation

Even with professional equipment, expect 0.1-0.3 second variation between runs due to driver technique, tire temperature, fuel load, and environmental factors. If your times vary by more than 0.5 seconds, check your GPS signal and phone mounting.