An ETA changes because the app is repeatedly estimating the remaining route from new information. A jump does not necessarily mean the app failed; it can reflect traffic, a route change, inaccurate location, or a destination delay that was not part of the original drive time.
What feeds an ETA
- Your current location and direction of travel
- The selected route and remaining distance
- Observed and historical traffic speeds
- Crashes, construction, closures, and reported disruptions
- Turns, intersections, road type, and route changes
Google explains that navigation data—including GPS position, chosen route, and device sensor data—contributes to traffic conditions and faster-route suggestions. Its current overview is How navigation data makes Maps better.
Common reasons for a sudden increase
- A crash or closure reduced speed ahead.
- The route entered a recurring queue later than predicted.
- The phone briefly placed the vehicle on a frontage or parallel road.
- A missed turn added distance or a slow turnaround.
- The app switched to an alternate with a different traffic pattern.
- The final entrance or parking delay was never included.
Why an ETA can improve
A queue may clear, a reported incident may be removed, the vehicle may pass the slow segment, or the app may find a faster legal route. Treat a small improvement as an updated estimate, not time that should be recovered by driving faster.
Make the arrival plan more stable
- Verify the destination and entrance before departure.
- Use a departure-time prediction and add a purpose-based buffer.
- Keep precise location and the map app functioning correctly.
- Download offline coverage for data gaps.
- Avoid switching routes for a very small theoretical gain.
- Share an arrival range rather than one exact minute when others are waiting.
When the jump suggests a phone problem
If the blue dot jumps between roads, points in the wrong direction, or lags far behind the vehicle, troubleshoot location accuracy. If the dot is stable and the traffic layer changes, the new ETA is more likely related to route conditions.
Do not manage the ETA while moving
Let a passenger inspect alternatives. When driving alone, continue safely and stop before changing settings or comparing routes. A missed turn is safer than a sudden maneuver intended to preserve an estimate.
Related guidance
- Choose a more reliable departure window
- Check whether location error is changing the ETA
- Fix repeated route recalculation
Reviewed July 19, 2026. ETA calculations are proprietary and vary by provider; this page describes observable inputs, not a provider's complete algorithm.