What3words for Precise Positioning: Pros, Cons & Accuracy

Yes, what3words can be used for precise positioning, but it is not a standalone GPS system—it is an addressing overlay that converts GPS coordinates into three-word labels. You still need a GPS-enabled device to determine your location, and the service is most reliable when you have a clear view of the sky. This article explains how what3words works, its accuracy, limitations, and how it compares to traditional coordinates.

What Is what3words?

what3words is a geocoding system that divides the Earth’s surface into 3-meter by 3-meter squares, each assigned a unique combination of three words. The system uses a fixed algorithm to map every square to a trio of words from a list of about 40,000 words. This makes it easier for humans to communicate locations than long strings of numbers, especially in emergency situations or when sharing a spot with someone who lacks a street address.

The service is proprietary, and its algorithm is not open source. However, the company provides free apps for iOS and Android, as well as a web-based map. The words are chosen to be distinct and avoid homophones, and the system works in over 50 languages.

How Does It Achieve Precision?

The precision of what3words comes from its grid size. Each square is 3 meters by 3 meters, which is roughly the size of a small car. This is more precise than a typical street address, which might cover an entire building or block. When you share a what3words address, you are pinpointing a specific 9-square-meter area.

The underlying coordinates are based on the WGS 84 datum, the same used by GPS. The algorithm converts latitude and longitude into three words using a mathematical mapping. The accuracy of the final position depends on the GPS receiver in your device. In open sky conditions, most smartphones achieve an accuracy of about 5 to 10 meters, which is slightly larger than the grid square. In urban canyons or indoors, accuracy degrades significantly.

How to Use what3words Effectively

To get the most out of what3words, follow these steps:

• Download the official what3words app or use the web map.
• Ensure your device’s GPS is enabled and you have a clear view of the sky.
• Wait a few seconds for the blue dot to stabilize before reading your three words.
• When sharing, always include the full three words in the correct order, as the system is case-sensitive and order matters.
• If you are in a remote area, download offline maps in advance, as the app works without a cellular signal.

For emergency use, the app can automatically share your location with emergency services in some countries, but this feature depends on local integration.

Common Problems and Misconceptions

One common misconception is that what3words replaces GPS. It does not—it simply formats GPS coordinates. Another is that the three words are random; they are actually assigned algorithmically, and similar-sounding words are avoided to prevent confusion.

Problems arise when users enter the words in the wrong order or misspell one. A single typo can place you miles away. Also, the system uses English words by default; if you switch languages, the same square will have different words, which can confuse international teams. Finally, the 3-meter grid is not absolute; GPS error means the actual position can be off by several meters, so it is not suitable for tasks requiring centimeter-level accuracy, such as surveying.

What3words vs. Standard Coordinates

Standard GPS coordinates (latitude/longitude) are more precise and universally understood by mapping systems. They can be expressed in decimal degrees, degrees/minutes/seconds, or UTM. However, they are prone to human error when read aloud or typed—a single digit mistake can be catastrophic. What3words is designed to be easier for humans to remember and communicate, but it adds a layer of proprietary encoding that requires the what3words app or website to decode.

For professional use, such as GIS or navigation, standard coordinates are preferred because they are open and interoperable. For casual sharing or emergency response, what3words can be faster and less error-prone. Some emergency services have adopted it, but not all, so it is wise to know your coordinates as a backup.

Cost and Accessibility

The what3words app is free for personal use. The company makes money through business licensing, such as integrating the system into logistics, ride-hailing, or navigation apps. There is no cost to share a three-word address with someone else, as they can use the free app to decode it.

Accessibility is a strong point: the words are chosen from a limited vocabulary, making it easier for non-native speakers or those with literacy challenges. Offline mode is available, which is crucial in disaster zones or remote wilderness. However, the system relies on the availability of the app; if the service were discontinued, the addresses would become useless.

Safety and Privacy Considerations

Sharing a what3words address is equivalent to sharing your exact GPS coordinates. This can be a safety risk if you are sharing your home location publicly. Be cautious about posting three-word addresses on social media, as they can be used to locate you. The app does not require an account to use, but if you create one, your data is subject to the company’s privacy policy.

In emergency situations, what3words can save lives by providing an unambiguous location. But it is not a substitute for knowing your surroundings. Always carry a physical map and a compass if you are venturing into remote areas, as electronic devices can fail.

Frequently Asked Questions

Is what3words accurate enough for emergency services?

In many cases, yes. The 3-meter grid is more precise than a street address, and emergency call centers in some countries can receive what3words locations directly. However, the accuracy depends on the GPS signal. If you are indoors or in a canyon, the position can be off by tens of meters, so emergency services still rely on additional information.

Can I use what3words without an internet connection?

Yes. The app allows you to download offline maps for a region, and the three-word addresses are generated locally on your device. You do not need a cellular signal to see your current three words, but you will need a GPS fix, which works without internet.

What happens if I type the words in the wrong order?

You will get a different location, often far from the intended one. The app will show a warning if the words are in the wrong order, but it will still show you the location for the entered sequence. Always double-check the order.

Are the three words unique globally?

Yes, every 3-meter square on Earth has a unique three-word address. There is no duplication. The algorithm ensures that similar-sounding words are not used together to avoid confusion.

Can I convert a what3words address to standard coordinates?

Yes. The app displays the latitude and longitude for any three-word address. You can also use the website to enter a three-word address and get the coordinates. This is useful for sharing with someone who does not use what3words.

Is what3words free for businesses?

No. Businesses must purchase a license to integrate what3words into their products or services. The free app is for personal, non-commercial use only.

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