How accurate is phone GPS?

What GPS accuracy means

GPS accuracy is how close the position your device reports is to where you really are. GPS.gov separates two things. The signal the satellites broadcast is very precise: the government commits to a daily global average user range error of 2.0 meters (6.6 feet) or less, with 95% probability. But what you actually experience depends on satellite geometry, that signal error, and local factors such as blockage and the quality of your receiver.

A phone is a compact receiver with a small antenna, so it is more affected by its surroundings than professional equipment. GPS.gov notes that high-end users reach accuracy within a few centimeters in real time using dual-frequency receivers and augmentation systems. Your phone is not that, and it does not need to be for sharing where you are on a run.

What makes phone GPS drift

You see this as a dot on the wrong side of the street, a track that cuts corners, or a zigzag while you stand at a crosswalk. None of it means the phone is broken. It is normal GPS behavior near obstacles.

• Blockage: buildings, bridges, trees and terrain hide part of the sky
• Multipath: signals reflect off buildings or walls before reaching you
• Being indoors or underground, where signals are weak or absent
• Radio interference or jamming
• Major solar storms, which GPS.gov also lists

What to expect by terrain

GPS.gov gives one number, for open sky. Everywhere else the direction is clear even if the size of the error varies by phone and place.

What it means on a run, ride or hike

For following someone's progress, typical phone accuracy is plenty. A Guardian watching a breadcrumb trail can tell which road or trail you are on, which way you are heading and roughly how far you have gone.

It matters more when someone needs to find you. A few meters off on an open road is trivial. Under a thick forest canopy or in a narrow canyon, the error can grow, and the last point sent might be some distance from where you stopped. Searchers should treat a phone location as the center of an area, not an exact spot.

Here is how that plays out. A rider's partner sees his dot stop beside a river on a wooded gravel road, apparently in the water. It is multipath and tree cover, not a crash into the river: he is on the road, 20 yards away, fixing a flat. Knowing the dot can be off keeps the partner calm, and knowing the route line tells her which road to name if she ever needs to call.

Drift also affects features that watch for stillness. A phone lying on the ground can still appear to wander a little, which is why a good stationary alert uses a distance threshold rather than expecting the dot to freeze.

GPS accuracy vs signal coverage

These are two different things that people often mix up. GPS works without any cell service; your phone can know where you are in the middle of nowhere. What it cannot do without a network is tell anyone else. That is the cell dead zone problem, not a GPS problem.

This is why offline maps can show your position on a remote trail while a live sharing app stops updating. Our answer on whether live location sharing works without cell signal explains the difference in more detail.

Getting a better fix

Battery matters too. Some phones take location readings less often in low power modes. Our answer on how much battery live location sharing uses covers the trade-off.

How Holler handles it

Holler uses your phone's location to update a private live link for your Guardians. The map shows your latest position and the route behind it, plus how long ago the location last updated. The dot is only as accurate as your phone's GPS at that moment, so treat it as close, not exact.

Its optional stationary alert asks "Are you OK?" when you stop moving for the time you choose, and alerts your Guardians if you do not answer. When signal drops, updates pause and your Guardians see your last known location, marked as stale. See how the pieces fit in live location sharing.