Google Maps Android Auto speedometer bug: km/h switches to mph
Users report that the Google Maps speedometer in Android Auto can switch from km/h to mph even when metric units remain selected. Google has not explained this specific bug.
The Google Maps speedometer in Android Auto has started switching from kilometres per hour to miles per hour on its own while people are driving. The most frustrating part is that the app setting can still remain on km/h, so simply changing the unit setting does not solve the problem. The first complaints appeared on September 22–23.
According to user reports, the bug is still intermittent and appears mainly among people who use the metric system. For some, mph stays on the screen until Maps is restarted; for others, the app switches back to km/h fairly quickly. There is no confirmation that the issue is widespread, and Google has not publicly explained this specific fault.
The timing is especially noticeable because Google has only recently expanded the feature. The speedometer started appearing in Android Auto over the summer, and in September Google continued rolling it out so it can work even without an active route. New system builds are arriving at the same time: the Android Auto 17.8.1638 beta recently brought another package of bug fixes and other improvements, but there is no confirmation that it resolves the mph/km/h switching problem.
There is no permanent fix yet. As a temporary workaround, some users are restarting Google Maps. That should not be done while the vehicle is moving: it is safer to stop first and only then restart the app. The km/h setting can remain enabled even when Android Auto is already showing mph.
There is also an important limitation to the feature itself. Google explicitly warns that the Maps speedometer is for informational use only and that the vehicle's own speedometer should be used to confirm actual speed. The company also notes that external factors can cause Maps to show a different figure from the real speed.
For drivers, the main reference therefore does not change: if Android Auto suddenly shows mph or a suspicious number, do not try to convert the speed while driving and do not get distracted by the phone. The vehicle's built-in speedometer remains the primary source until Google releases a fix.