Proprietary geocoding system

What3words Ltd.
What3words Company Logo
What3Words example.svg
Part of the What3Words grid on the Palace of Westminster showing typical words and their pseudorandom distribution
Trade name
Founded2013; 9 years ago (2013)
  • Chris Sheldrick
  • Jack Waley-Cohen
  • Mohan Ganesalingam
  • Michael Dent
HeadquartersLondon, England, UK

What3words is a proprietary geocode system designed to identify any location with a resolution of about 3 metres (9.8 ft). It is owned by What3words Limited, based in London, England. The system encodes geographic coordinates into three permanently fixed dictionary words. For example, the front door of 10 Downing Street in London is identified by ///slurs.this.shark.[1]

What3words differs from most location encoding systems in that it uses words rather than strings of numbers or letters, and the pattern of this mapping is not obvious; the algorithm mapping locations to words is protected by copyright.[2]

The company has a website, apps for iOS and Android, and an API for bidirectional conversion between what3words addresses and latitude/longitude coordinates.


Founded by Chris Sheldrick, Jack Waley-Cohen, Mohan Ganesalingam and Michael Dent, what3words was launched in July 2013.[3][4] Sheldrick and Ganesalingam conceived the idea when Sheldrick, working as an event organizer, struggled to get bands and equipment to music venues using inadequate address information.[5] Sheldrick tried using GPS coordinates to locate the venues, but decided that words were better than numbers after a one-digit error led him to the wrong location. He credits a mathematician friend for the idea of dividing the world into three-metre squares, and the linguist Jack Waley-Cohen with using memorable words.[6] The company was incorporated in March 2013[7] and a patent application for the core technology filed in April 2013.[8] In November 2013, what3words raised US$500,000 of seed funding;[9]

Following initial unsuccessful attempts to become profitable as a consumer-focused offering, What3words switched to a business-to-business model.[10] In January 2018, Mercedes-Benz bought approximately 10% of the company and announced support for What3words in future versions of the Mercedes-Benz User Experience infotainment and navigation system.[11] The A-Class, launched in May 2018, became the first vehicle in the world with What3words on board.[12]

In March 2021 it was announced that ITV plc had bought a £2.7 million stake in What3words to gain access to advertising space.[13]

In 2018 the company had a turnover of £274,000 and lost £11M.[10] In the year ending December 2019, the company lost £14.5M and had reported assets of £24.7M.[13] By January 2020 the company had reached 100 employees and raised over £50M from investors.[10]

Design principles

What3words divides the world into a grid of 57 trillion 3-by-3-metre squares, each of which has a three-word address. The addresses are available in 50 languages.[14] Translations are not direct, as direct translations to some languages could produce more than three words. Rather, territories are localised considering linguistic sensitivities and nuances.[15]

Each what3words language uses a list of 25,000 words (40,000 in English, as it covers sea as well as land). The company says they do their best to remove homophones and spelling variations;[16] at least 32 pairs of near-homophones still remain.[17]

What3words originally sold "OneWord" addresses, which were stored in a database for a yearly fee,[18] but this offering has been discontinued.[19] The company states that densely populated areas have strings of short words due to more frequent usage; while less populated areas, such as the North Atlantic, use more complex words.[15][6]

Co-founder and CEO Sheldrick claims "Whilst the overwhelming proportion of similar-sounding three-word combinations will be so far apart that an error is obvious, there will still be cases where similar sounding word combinations are nearby."[20] According to Rory Sutherland from the advertising agency Ogilvy in an op-ed piece for The Spectator, the system's advantages are memorability, error-detection, non-ambiguity of words for most everyday and non-technical uses, and voice input.[21]

Emergency Services

In September 2019, the Scottish Ambulance Service used the app to locate an injured hillwalker.[22] As of September 2021, more than 85 per cent of British emergency services teams use what3words, including the Metropolitan Police and London Fire Brigade.[23][24]

In Feb 2020, it was first used in a rescue operation in Australia.[25] What3Words was subsequently built into the Australian Government’s Triple Zero Emergency Plus App.[26]

In February 2020, in Singapore, the system was used to help rescue 2 lost 14 year old boys.[27]

The service is also used by Los Angeles Fire Department,[28] Austin City,[29] and Kansas[30] Emergency Services, and was used to rescue kayakers in Deerfield in August 2022[citation needed] and in Mobile Bay, Alabama in July 2022.[31] In Canada the system is used by Ontario emergency services,[32] and helped Halton emergency services rescue a woman hit by a rock whilst climbing.[33]

It is used by mountain rescue and emergency teams in Bavaria[34] and Lower Saxony[35] in Germany.


The company sells its technology to logistics companies, taxi services, automotive manufacturers, post offices and couriers.[36]


Not an open standard

Supporters of open standards criticise the What3words system for being controlled by a private business and the software for being patented and not freely usable.[24]

The company has pursued an assertive policy of issuing copyright claims against individuals and organisations that have hosted or published files of the What3words algorithm or reverse-engineered code that replicates the service's functionality, such as the free and open source implementation WhatFreeWords.[37] The whatfreewords.org website was subsequently taken down following a Digital Millennium Copyright Act (DMCA) take-down notice issued by What3words. This has extended to removing comments on social media which refer to unauthorised versions. In late April 2021, a security researcher was subjected to the threat of a lawsuit from What3words, stating that linking to the open source reimplementation "WhatFreeWords" violates the company's copyright.[38] "The letter also demanded that he disclose to the [company's lawyers] the identity of the person or people with whom he had shared a copy of the software, agree that he would not make any further copies of the software and to delete any copies of the software he had in his possession."[38]

Words are not culturally neutral

In a 2019 blog, Open standards advocate and technology expert Terence Eden questioned the cultural neutrality of using words rather than the numbers generated by map coordinates. "Numbers are (mostly) culturally neutral." he said, "Words are not. Is mile.crazy.shade a respectful name for a war memorial? How about tribes.hurt.stumpy for a temple?"[24]

Similar addresses can be close

What3words state that similar addresses are spaced as far apart as possible to avoid confusion,[39] and that similarly-sounding codes have a 1 in 2.5 million chance of pointing to locations near each other.[40] However, security researcher Andrew Tierney calculates that 75% of What3words addresses contain plural words that also exist in singular form (or the reverse).[17] Further analysis by Tierney shows that in the London area, around 1 in 24 addresses will be confusable with another London address.[41]

Incorrect addresses

In December 2019, the Lake District Search & Mountain Rescue Association noted that "mishearing or misspelling words tended to cause problems" and warned hikers not to rely on it.[42]

In June 2021 Mountain Rescue England and Wales raised concerns about the credibility of reported What3words coordinates, following incorrect information being given about 45 locations over 12 months. Spelling issues and local accents were reported as being part of the problem.[43]

In September 2022, the Department of Culture, Media and Sport used What3words to direct mourners to the end of the queue to view the Queen lying in state in London. Of the first five codes published, four led to the wrong place,[44] including a suburb of London some 15 miles from the real end of the queue.[45] Officials later moved to an automated system to generate the identifiers, as they realised having people involved in the process resulted in typos.[44]


The site has been parodied by others who have created services including What3Emojis[46] using emojis, What3Birds[47] using British birds, What3fucks[48] using swear words, Four King Maps[49][50] also using swear words (covering only the British Isles), and What3Numbers[51] using OpenStreetMap tile identifiers.


See also


  1. ^ Leatherdale, Duncan (15 August 2019). "What3words: The app that can save your life". BBC News. Retrieved 31 January 2021.
  2. ^ "What3Words sent a legal threat to a security researcher for sharing an open-source alternative". TechCrunch. Retrieved 11 November 2021.
  3. ^ "'What3Words' Wants To Replace Postcodes With Words – For The Entire Globe". HuffingtonPost. 2 July 2013.
  4. ^ "Location-Pinpointing Startup what3words Sells 10,000+ OneWord Map-Pins In First Week". Techcrunch. 8 July 2016.
  5. ^ Lanks, Belinda (11 October 2016). "This App Gives Even the Most Remote Spots on the Planet an Address". Magenta.as.
  6. ^ a b Margolis, Johnathan (20 October 2015). "What3Words: new tech that will find any location". Financial Times. Retrieved 15 June 2021.
  7. ^ "WHAT3WORDS LIMITED - Overview (free company information from Companies House)". Companies House.
  8. ^ "A Method and Apparatus for Identifying and Communicating Locations". World Intellectual Property Organization.
  9. ^ "Startup what3words gets USD 500,000 in seed round". Venture Capital Post.
  10. ^ a b c Sam Shead (15 January 2020). "A navigation startup pivots and grows, but profitability is still down the road". Business Insider.
  11. ^ "Why Daimler Invested in a Startup That Has Labeled the World With Unique Three-Word Addresses". Fortune. 11 January 2018.
  12. ^ Brecht, Michael (5 April 2018). "What3words: Diese Ortungssoftware gibt es bald serienmäßig in Daimlers A-Klasse". Die Welt.
  13. ^ a b Stephen Lepitak (25 March 2021). "British Broadcaster ITV Invests $2.7 Million in Location Finding Platform What3words". Adweek.
  14. ^ "Celebrating 50 Languages". Official website - what3words.com.
  15. ^ a b Lo Dico, Joy (6 February 2021). "Postcodes from the edge: how an upstart app is changing the world's addresses". Financial Times. Retrieved 15 June 2021.
  16. ^ "How do you take into account words that sound the same or can be spelled in different ways?". What3words support. Archived from the original on 9 August 2020. Retrieved 9 August 2020.
  17. ^ a b Tierney, Andrew (29 April 2021). "Why What3Words is not suitable for safety critical applications" (PDF). Mountain Rescue. No. Summer 2021. p. 30. ISSN 1756-8749.
  18. ^ Lomas, Natasha (8 July 2013). "Location-Pinpointing Startup what3words Sells 10,000+ OneWord Map-Pins In First Week". TechCrunch.
  19. ^ "Why can't I buy my own words or change some of the words?". what3words.
  20. ^ Wakefield, Jane (29 April 2021). "App used by emergency services under scrutiny". BBC News. Retrieved 16 June 2021.
  21. ^ Rory Sutherland (25 October 2014). "The best navigation idea I've seen since the Tube map". The Spectator. Archived from the original on 5 January 2015.
  22. ^ "'Life-saving' app used in Western Isles hillwalker rescue". BBC News. BBC. 28 September 2019.
  23. ^ Moules, Jonathan (26 September 2021). "Chris Sheldrick of What3words: lessons from scaling a start-up". Financial Times.
  24. ^ a b c "What3words: 'Life-saving app' divides opinion". BBC News. 21 September 2019.
  25. ^ Power, Julie (18 May 2020). "Three random words saved Cornelia on a cold wet day of bushwalking". Sydney Morning Herald.
  26. ^ "Triple Zero". Australian Government. Australian Government.
  27. ^ "Boys, 14, got lost in MacRitchie forest trying to find a shrine". Straights Times. 1 November 2020.
  28. ^ Staff (8 September 2021). "What3Words App Connects LAFD To People In Need Of Help Faster". CBS News.
  29. ^ Staff (12 March 2022). "This app and three words could save your life". Kxan.
  30. ^ "Three words that can keep your family safe, police say". KSNT 27 News. 27 September 2022. Retrieved 29 September 2022.
  31. ^ Pippin, Cory (20 July 2022). "Kayaker floating in Mobile Bay rescued thanks to Baldwin Co. 9-1-1 GPS technology". WPMI. Retrieved 29 September 2022.
  32. ^ Nick Westol (12 March 2022). "What3words app increasingly being used by Ontario's emergency services to find people who are lost". global news.
  33. ^ "Milton rock climbing incident leaves woman with serious injuries". www.insidehalton.com. Retrieved 29 September 2022.
  34. ^ "Bei Tröstau: Helfer üben gemeinsam - Frankenpost". www.frankenpost.de (in German). Retrieved 29 September 2022.
  35. ^ Hallo Niedersachsen: Geländerettung im Deister: Mit dem E-Bike zum Patienten (in German), retrieved 29 September 2022
  36. ^ Margolis, Jonathan (20 October 2015). "What3Words: new tech that will find any location". Financial Times.
  37. ^ "DMCA takedown of code on Github". GitHub. 5 July 2016.
  38. ^ a b Whittaker, Zack (30 April 2021). "What3Words sends legal threat to a security researcher for sharing an open-source alternative".
  39. ^ "How are the words assigned?". What3words support. Archived from the original on 9 August 2020. Retrieved 9 December 2020.
  40. ^ "App used by emergency services under scrutiny". BBC News. 29 April 2021. Retrieved 29 April 2021.
  41. ^ "What3Words The Algorithm". 20 September 2021. Retrieved 20 September 2021.
  42. ^ Humphries, Will (26 December 2019). "Don't rely on location app What3words, say rescuers". The Times. Retrieved 20 September 2022.
  43. ^ Wakfield, John (1 June 2021). "Rescuers question what3words' use in emergencies". BBC. Retrieved 1 June 2021.
  44. ^ a b Turner, Camilla (14 September 2022). "Mourners sent to back of the queue (in California) as tracking system suffers early blips". The Telegraph. ISSN 0307-1235. Retrieved 19 September 2022.
  45. ^ Stokel-Walker, Chris (14 September 2022). "UK Government Sends Mourners to North Carolina to Queue for the Queen". Gizmodo. Retrieved 19 September 2022.
  46. ^ "what3emojis". what3emojis.com.
  47. ^ "Location Encoding Systems". checkmypostcode.uk. What3Birds...is a parody of the commercial What3Words system, which isn't suitable for this website as it doesn't have a published, open source algorithm. It does, though, work - every postcode on this website has a unique, three bird code. The list of birds was taken (in simplified form) from the British Ornithologists' Union's official list of birds recorded in Britain.
  48. ^ "what3fucks". Archived from the original on 5 December 2019.
  49. ^ "Four King Maps".
  50. ^ Corfield, Gareth (14 August 2021). "Tired: What3Words. Wired: A clone location-tracking service based on FOUR words – and they are all extremely rude". The Register. London. Retrieved 24 December 2021.
  51. ^ "what3numbers". Github.io.
  52. ^ Diaz, Ann-Christine (26 June 2015). "What3Words Innovation Grand Prix Cannes – Special: Cannes Lions – Advertising Age". adage.com.
  53. ^ "San Jose: Tech awards honor an array of laureates". Mercury News. 12 November 2015.

External links

  • Company website
  • Tierney, Andrew (29 April 2021). "Why What3Words is not suitable for safety critical applications".
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