GPS Performance & Distance Accuracy | Support

GPS Performance & Distance Accuracy

Last updated: April 15, 2026 · Applies to: iPhone (iOS 16+)

Earn Your Ears uses your iPhone's GPS to track distance, pace, and location during races and training runs. This article explains what kind of accuracy to expect, why your distance may differ slightly from an Apple Watch or other running apps, and what you can do to get the best results.

What accuracy should I expect?

In normal conditions, Earn Your Ears tracks distance within 1–3% of your actual distance. On a 10K (6.2 miles), that means the app and your Apple Watch might differ by 0.05–0.15 miles. On a half marathon, the difference might be up to 0.2–0.3 miles.

This is normal. No two GPS devices will show the exact same distance — even two Apple Watches on the same wrist will disagree slightly. Small differences between the app and your watch are expected and don't mean either device is wrong.

Why doesn't it match my Apple Watch exactly?

There are several reasons why Earn Your Ears and your Apple Watch may show slightly different distances:

Factor	What's happening
Different GPS chips	Your iPhone and Apple Watch have separate GPS hardware. They receive slightly different satellite signals and process them independently.
Wrist vs. pocket	An Apple Watch on your wrist has a clearer view of the sky than a phone in an armband, belt, or pocket. Better sky visibility generally means better accuracy.
Accelerometer assist	Apple Watch uses its built-in accelerometer and motion sensors to supplement GPS and estimate stride length. The iPhone app relies on GPS signals only.
Smoothing algorithms	Every running app applies its own math to filter out GPS noise. Different algorithms produce slightly different results — neither is "wrong," they're just different approaches to the same noisy data.
Sample rate	Different devices and apps record GPS points at different intervals. More frequent readings generally produce more accurate distance — but also more noise to filter.

The bottom line: If your distance is within 1–3% of your watch, both devices are working correctly. The "true" distance of any run is always an estimate — even certified race courses have a small margin of error.

Tips for Best GPS Accuracy

Follow these tips to get the most accurate distance tracking from Earn Your Ears:

1 Set location permissions to "Always Allow"

Go to Settings > Privacy & Security > Location Services > Earn Your Ears and select Always. This ensures GPS tracking continues when your phone is locked or in your pocket. Without this, tracking will stop when the screen turns off.

2 Give GPS a moment to lock on

Start your run or race session 30–60 seconds before you begin moving. This gives the GPS time to acquire strong satellite signals. You'll see more accurate results from the very first step.

3 Keep your phone in a stable position

An armband, running belt, or secure pocket works best. Holding your phone in your hand or letting it swing freely can introduce extra GPS noise from the movement.

4 Stay in open areas when possible

GPS works best with a clear view of the sky. Tall buildings, dense tree cover, tunnels, and indoor sections (like castle underpasses at Disney) can temporarily reduce accuracy. The app handles these gaps automatically, but open areas will always give the cleanest signal.

5 Make sure you're on the latest build

We regularly improve the GPS smoothing algorithm based on real-world testing. Close the app completely and reopen it before a run to make sure you have the latest update. You can check your build number on the home screen under the greeting.

runDisney tip: Disney race courses include tunnels, backstage corridors, and covered areas that temporarily block GPS signals. Don't worry — the app will reconnect and resume tracking as soon as you're back in an open area. Your overall distance will still be accurate.

Troubleshooting

My distance is significantly off (more than 5%)

This usually means GPS tracking was interrupted. Check that your location permission is set to "Always" (not "While Using App"). Also make sure Low Power Mode is turned off — it can reduce GPS update frequency. If the issue persists, check the Troubleshooting Log (Profile tab > Troubleshooting Log) and send us a screenshot.

Distance seems to jump or spike suddenly

This can happen when you move from a GPS-blocked area (like a tunnel) back into open sky. The phone receives a burst of location updates and temporarily registers extra distance. The app's smoothing algorithm filters out most of these spikes, but extreme cases can occasionally slip through.

The app shows 0.00 miles and isn't tracking

This usually means location permissions aren't set correctly. Go to Settings > Privacy & Security > Location Services > Earn Your Ears and confirm it's set to Always. If it's already set correctly, try closing the app completely (swipe up from the app switcher) and reopening it to restart the GPS session.

Distance is accurate for the first mile but drifts over time

Small differences accumulate over distance — this is normal for GPS tracking. A 1% difference on one mile is barely noticeable, but over a half marathon it adds up to a quarter mile. If you're seeing more than 3% drift, check that the app has the latest build and that your phone has a clear GPS signal.

My pace numbers seem wrong even though distance looks right

Pace is calculated from distance and time, so even a small distance variation can shift your pace by several seconds per mile. Current pace is especially sensitive because it's calculated over a short window. Average pace is more reliable and should closely match your watch over the full run.

GPS seems worse in certain areas of the Disney parks

Some areas of Disney property have heavier tree cover, buildings, or backstage corridors that interfere with GPS. This is a known limitation of all GPS devices in these areas — your Apple Watch will experience the same signal degradation. The app will recover once you're back in an open area.

Checking Your GPS Data After a Run

After completing a training run, the app shows a GPS diagnostics panel with useful information:

GPS points recorded — how many location readings were captured during your run
Average accuracy — the average horizontal accuracy of those readings (lower is better; under 10m is excellent)
Export GPS Log — exports your raw GPS data as a CSV file you can share with us for troubleshooting

If you're experiencing accuracy issues, this data helps us diagnose the problem. Tap Export GPS Log and send it to us along with a description of what seemed off.

Still Having Issues?

If your GPS accuracy doesn't improve after trying the steps above, we want to help. Send us the following:

A screenshot of your Troubleshooting Log (Profile tab > Troubleshooting Log)
Your GPS export file (if available)
What distance the app showed vs. what your watch showed
Where you were running (park, neighborhood, treadmill, etc.)

Email Support

support@earnyourears.app · We typically respond within 24 hours

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