How does what3words handle similar combinations of words?


We’ve designed our map to try to avoid placing addresses made of similar word combinations near each other (as much as possible). For example, ///table.chair.lamp is located in New South Wales, Australia, while ///tables.chair.lamp is in Minnesota, USA. This means that the overwhelming proportion of similar 3 word combinations are so far apart that an error is easy to spot.

When a what3words address is typed into a checkout page or search bar, AutoSuggest helps you spot and correct mistakes by displaying similar what3words addresses along with their distance from the user.

Of course, with over 57 trillion squares on our map, there are a handful of instances where potentially similar what3words addresses may be close to each other. However, the chance of these combinations appearing ambiguously in nearby areas in the UK is estimated at about 1 in 2.5 million. This, combined with the fact that what3words addresses are rarely used on their own and usually shared with additional information, means errors are quite unlikely.

For emergency services specifically, what3words addresses given by callers are verified by other methods to ensure their accuracy. For example, call handlers may encourage callers to to give additional descriptions of the location for verification. Currently, 85% of emergency services in the UK use what3words, with increasing numbers across the US, Canada, Australia, Germany, and elsewhere. We have received excellent feedback from enabled agencies: 100% of services that responded to our survey described what3words as ‘a reliable tool to have as part of the emergency toolkit’.