How do I tell 999 exactly where I am?

Lead with the road number or name and the direction you were travelling, then add the nearest junction, landmark or marker post. If you have the what3words app, give the three word address as well — it identifies a three-metre square. Give both rather than relying on either alone.

Do UK emergency services accept what3words?

Widely, but not universally. what3words states that over 85% of UK police, ambulance and fire services use it, and call handlers accept three word addresses on 999 calls. Its own guidance still advises gathering as much location information as you can, in case a three word address cannot be accepted on a particular call.

Does what3words work without a phone signal?

The app can determine your three word address offline, because it converts GPS coordinates using an algorithm held on the device rather than by looking them up online. You still need enough signal to make the 999 call itself, and you need the app already installed, since you cannot download it without data.

How accurate is a what3words address?

Each three word address identifies a three-metre square. That is far more precise than a road name on a long stretch of carriageway, but it is only as accurate as your phone's GPS fix at the time, which can drift under tree cover, between tall buildings or in tunnels.

Why does the exact location matter so much on a motorway?

Because a carriageway can run for miles between junctions, both sides are physically separated, and responders reaching the wrong side may have a long detour to turn around. Direction of travel and the nearest junction or marker post matter as much as the point itself.

Should I use what3words for my insurance claim as well?

It is a useful addition to your record, because it fixes precisely where the vehicles were rather than approximately which road. Record it alongside the road name, direction, nearest junction and the time, since an insurer or solicitor reading the file months later needs the plain description as well as the coordinates.

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Using what3words to Report Your Exact Accident Location

"Somewhere on the A34 past Newbury" can cover fifteen miles of dual carriageway with a barrier down the middle. A what3words address narrows it to a three-metre square, and most UK emergency services accept one on a 999 call. Give it alongside the road and direction, never instead of them.

Last updated 5 August 2026 · Applies across the UK

What it is

what3words divides the world into three-metre squares and gives each one a unique combination of three words. Instead of reading out coordinates, you say three ordinary words and the call handler sees the exact square.

It matters after a crash because the two hardest questions on a 999 call are often "where are you?" and "which side?" — and a shaken driver on an unfamiliar road frequently cannot answer either.

How widely it is accepted

what3words states that over 85% of UK police, ambulance and fire services use it, and that call handlers accept three word addresses on 999 calls. It is used by a range of responders including the UK Coastguard.

85% is not everyone, and this is what3words' own figure. Their guidance is to gather as much location information as you can, in case a three word address cannot be accepted on that particular call. Treat it as a powerful addition to conventional location details, not a replacement for them.

What to say on the call

Lead with what every call handler can use, then add the precision:

Road and direction first

"M40 northbound" or "A34 southbound towards Winchester." Direction is critical on any dual carriageway or motorway — the wrong side can mean miles of detour for responders.
Nearest fixed reference

The last junction you passed, a driver location sign, a marker post, a bridge, a village name, a house number. Motorway driver location signs give the road, direction and distance and are designed for exactly this.
Then the three words

Say them clearly and offer to spell any that could be misheard. Confirm the handler has read them back correctly.
What they are coming to

How many vehicles, how many people, whether anyone is trapped or unconscious, whether the road is blocked, and whether there is fuel spillage or fire risk. This determines what gets sent.

Does it work without signal?

The app can work out your three word address offline — it converts your phone's GPS position using an algorithm stored on the device, rather than looking it up over the internet. GPS itself does not need mobile data.

Two caveats, both practical:

You still need enough signal to make the 999 call. In the UK, 999 can connect via any available network, not only your own.
You need the app already installed. You cannot download it with no data, and nobody installs an app while standing in a live carriageway.

How accurate is it really?

Each address identifies a three-metre square — but that is the resolution of the grid, not a guarantee about your phone. The square you are given is only as good as the GPS fix behind it, which can drift under heavy tree cover, between tall buildings, in tunnels or multi-storey car parks.

If the reported square looks wrong on the map, say so and fall back on landmarks. A handler would far rather have "outside the Red Lion on the B4009" than a confidently wrong three-metre square.

Beyond the 999 call

An exact location is worth recording for the claim as well. Months later, "the A34" tells an insurer nothing about the junction layout, the lane markings or the sightlines. A precise point lets anyone reading the file place the vehicles on a map and understand the geometry of what happened.

Record it alongside — never instead of — the road name and number, direction of travel, nearest junction, and the time. See our guide to documenting accident evidence for the rest of what to capture.

Set it up now, not later

Install the what3words app today, while you have data and a spare minute
Open it once so it has location permission and you know what the screen looks like
Learn the one gesture that shows your current address — under stress you will not explore a menu
Check your phone's location services are on

The location is one field of many

Knowing precisely where you are helps the ambulance find you. It does nothing for the claim that follows — that needs the photographs, the other driver's details, the witnesses and your account while it is still accurate.

Car Crash Lawyer AI captures your what3words location as part of a full incident record: emergency access to 999, photographs prompted in the right order, a spoken statement it transcribes, a DVLA check on the other vehicle from its registration, witness and police details, and your dashcam footage — assembled into an 18-page report and emailed to you.

£11.99 for a year. Like the what3words app itself, it only helps if it is already on your phone.

Get the app — £11.99 a year

Using what3words to Report Your Exact Accident Location

What it is

How widely it is accepted

What to say on the call

Road and direction first

Nearest fixed reference

Then the three words

What they are coming to

Does it work without signal?

How accurate is it really?

Beyond the 999 call

Set it up now, not later

The location is one field of many

Sources

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