Where am I? What your phone can actually tell you

The screen above this is the answer, and it has three parts: a name, a measurement, and a number saying how much of the name to believe. Most location apps show you the first and throw away the third. This one prints all three, because the third is what decides whether the first is worth anything.

What the sign is telling you

The big line is a name for a coordinate. It is not the coordinate.

Your device measures a latitude and a longitude. That is the measurement, and it is printed underneath. The name comes from asking a geocoder a much narrower question — what do you have a record of near this point? — and the answer is an interpretation of the measurement, made by a database that has never been where you are standing.

That is why the coordinates are on the screen rather than tucked away. They are the part that came from your device. Everything above them is a lookup.

Why the address can be wrong

A reverse geocoder returns the nearest thing it has a name for. That is the whole of what it does.

So it can be exactly right about its own records and still be wrong about you. Stand in a yard, on a path, at a set-back entrance, or in a building too new to be listed, and the nearest known address might be eighty metres away — somebody else's front door, printed under an excellent fix.

When that happens the app offers the other nearby candidates and lets you say which one you meant. Picking one changes the label and nothing else: the latitude, longitude, accuracy and elevation stay exactly as your device reported them, because none of them became different when you corrected a name. The choice is remembered on this device, for that patch of ground, and none of it is sent anywhere.

What the ± number means

Top right of the sign, in metres or kilometres. It is a radius, not a margin you can average away.

±8 m is a circle you could throw a ball across. ±3 km is a circle holding tens of thousands of front doors, and no version of that fix knows your street.

So the radius decides what the app is allowed to print. A good fix earns a house number. A worse one loses the number and keeps the street. Worse again and it gives you the neighbourhood, then a rough area — and a postcode has digits masked rather than shown in full, because a Dutch or British postcode is close enough to a doorstep that printing one you have not earned is a lie with an address attached.

This is why the app sometimes says less than the one beside it. That is the trade, and it is made on purpose.

When it says nothing at all

Two failures look alike and are not.

No position. The sensor produced nothing. Nothing has been measured, so nothing can be named, and moving outside or nearer a window is the fix — this is the one case where the sky really is the answer.

A position with no name. Your device knows exactly where it is and the lookup could not be reached. That is a network fault, not a location one. The coordinates on the screen are true, they are as precise as they ever were, and they can be copied and sent exactly as they stand. Positioning does not need a signal; only the name does.

Only the first is yours to fix. The second usually resolves itself, and the app keeps asking until it does.

If you want the reasoning rather than the summary — the two gates an address has to pass before it is printed, why a correction never moves your coordinates, and what all of this costs — it is written out in why your phone lies about where you are.

Questions people ask about this page

What is my current address?

The reading above is the street name and house number nearest to where your device believes it is standing, taken from OpenStreetMap. It sharpens as the position does.

Why does it show a street but no house number?

Two things have to be true before a number is printed: the accuracy circle has to be inside sixty metres, and the building the map matched has to be within twenty-five metres of you. If either fails, the street on its own is the honest answer.

How accurate is a phone GPS?

Outdoors under open sky, five to ten metres. Indoors, in a car, or between tall buildings it can be hundreds of metres — which is why the figure stays on screen instead of hiding behind a dot.

What is a plus code?

A short reference to one square on a global grid, worked out on your device. It needs no connection, it fits in a text message, and it opens in any maps app.

Does this site store my location?

No. Your coordinates go to our server, which asks the address and elevation providers on your behalf — so they never see your device — and are then gone. There is no account, and nothing about where you are is kept against you.