Contents: what3words

What is what3words?
Should I put what3words on my phone?
Displaying a national grid reference
Criticisms

What is what3words?

The w3w website says what3words is “the simplest way to talk about location” and gives the most remote locations on earth an address.

The entire planet has been covered in a grid of 3 metre squares. Each square has it’s own unique three-word address. A phone app and website make it easy to find and share any what3words address. If you see three slashes in front of three words separated by two full stops then you’re probably looking at a what3words address. eg ///boot.tent.dwell

The w3w phone app doesn’t need any phone signal or internet connection to provide a what3words address of your location. Like navigation apps it gets its location from the phone’s GNSS receiver. If you do use it in an area with no phone signal then you won’t see the base map, which is supplied by the internet, but the what3words address will be good anyway.

It’s a neat way to define any location and what3words makes it easy to describe your exact location even if you are in an unfamiliar area.

Type boot.tent.dwell into the what3words website or phone app to discover that it’s the centre of London Bridge.

In the UK, the what3words phone app can provide a 6, 8 or 10 digit Ordnance Survey grid reference too.

///brave.trickles.distorts is a wild swimming spot called Black Moss Pot, in the Lake District
///cuts.voted.perplexed is on Rhossili beach, south Wales

Should I put what3words on my phone?

Why not? In an emergency it’s important to be able to accurately share your location. The what3words app will not only provide your what3words address but the Ordnance Survey grid reference too (which mountain rescue teams prefer to use). The two could be cross-referenced by the emergency services to be sure of your location and help avoid telephone misunderstandings.

If your main navigation app failed the OS grid ref provided could still be used to pinpoint your location on an OS map. The w3w app also provides a simple way to convert a w3w address to an OS grid reference. Enter the w3w address into the app and the OS grid reference will appear under the w3w address.

In 2024 I was involved with an accident on Ben Nevis which required mountain rescue. To my surprise, the first thing I was asked about our location was the what3words address, not our OS grid reference. I was able to supply a grid reference, but it’s a sign of the times.

Some emergency services are encouraging people to put the app on their phones. eg The North East Air Ambulance service.

Most will be happy to receive a what3words address. Assuming you’ve space on your phone, it can’t do any harm to have this app as an option.

Displaying a national grid reference

The app won’t show a national grid reference by default. It needs enabling in ‘settings’. In the UK, you can choose a 6, 8 or 10 digit reference. You might as well choose the most accurate, a 10 digit reference, which defines a 1 metre square. The best modern GNSS receivers can be close to metre-perfect.

Criticisms of what3words

Some what3words addresses are very similar and it’s possible for errors to occur when sharing an address over the phone. If the similar address is for a location in another country then the error will be obvious. However, there are similar what3words addresses that are closer to each other. eg ///likely.stages.sock and ///likely.stage.sock are very close, on opposite banks of the River Clyde in the UK.

There have been occasions when a misheard what3words address has sent a rescue team to the wrong location. If you’d like more information on the kinds of errors that can occur then here’s a more detailed look.

It’s a commercial system that relies on the what3words technology. If the tech failed then it would be impossible to look up where a what3words address was. This isn’t a problem with OS grid references as every OS map numbers the grid lines. The same applies to lat/long coordinates.

To have an emergency service in the hands of a commercial company is uncomfortable.

If a business wants to use the technology they must pay for it. It’s proprietary and not free for everyone to use.