Why you shouldnt blindly trust the compass on your phone?

If you've ever used your phone's built-in compass and felt like something was off, there's probably something wrong with it. After testing a few models, there were a variety of issues, from inaccurate measurements to complete directional chaos.

Table of Contents

• How does a compass on a smartphone actually work?
• Not all compass apps are created equal
• Calibration is not always reliable
• Device inconsistency is a big problem
• What does this mean for navigation?
• Things you can do to improve accuracy
• Don't rely on your phone's compass in critical situations.

How does a compass on a smartphone actually work?

Your phone doesn't contain a conventional magnet. Instead, it uses a magnetometer, a sensor that detects magnetic fields. By combining this data with input from the gyroscope and accelerometer, the phone estimates which direction it's facing.

In theory, this is a smart approach. In practice, however, sensors are sensitive and susceptible to interference. Magnetic field measurements can be affected by everything from nearby metal desks and electronics to car dashboards. Even magnetic phone accessories can affect accuracy. The compass in your phone is constantly struggling with noisy and unpredictable environments.

Exploring the exciting innovations coming to smartphones can help us understand how future devices will handle more reliable compass functionality. Hopefully we’ll see improvements in accuracy and integration soon!

Not all compass apps are created equal

Many people assume that if a smartphone had a compass app, it would work as accurately and consistently as a traditional magnetic compass. Unfortunately, testing tells a different story. Using a variety of compass apps on a variety of smartphones, the author oriented each device in the same direction. The results were surprising.

Some apps work perfectly. Some are off by more than 100 degrees, confidently pointing to a brick wall instead of a door. Some compasses show different directions every time the app is opened. In some cases, the compass only responds correctly after shaking or rotating the phone.

This may sound counterintuitive, but it’s technically not a bug. Most compass apps rely on a combination of sensor and software calibration, which can vary greatly in quality and responsiveness. The accuracy of these apps depends not only on the hardware of your device, but also on how well the app interprets that data. To improve your experience, be sure to read user reviews and research reliable compass apps that may offer advanced features and potentially better accuracy.

Calibration is not always reliable

You may have seen the prompt: “Move your phone in a figure eight motion to calibrate.” Seems pretty straightforward. During testing, this calibration method sometimes worked and sometimes didn’t. Sometimes, calibration wasn’t necessary, until suddenly it was.

Part of the problem is the lack of standardization across devices. Some phones will automatically prompt you to recalibrate, while others require you to manually perform a unique calibration method to increase accuracy. Some phones may even adjust themselves in the background without any indication.

In the test, a phone that was constantly pointing west suddenly corrected itself after being spun in the air like a pizza. No warning. No feedback. Just a sudden return to accuracy.

Device inconsistency is a big problem

To better understand how smartphone compasses perform in real-world situations, we tested nine different phones in different locations, apps, and times of day. The lineup includes:

• iPhone 11
• iPhone 12 Pro Max
• iPhone 16 Pro
• Motorola Edge 2023
• Nothing Phone (1)
• Nothing Phone (3a)
• Nothing Phone (3a) Pro
• Xiaomi Poco X7 Pro
• Honor 200 Pro

The results were inconsistent. While some phones, like the iPhone 11 and the 2023 Motorola Edge, occasionally gave identical and accurate readings (after removing the magnetic case), most devices gave slightly different results under the same conditions. In some cases, the differences were extreme.

In one comparison, the Nothing Phone (3a) and Nothing Phone (3a) Pro — essentially the same device on paper — gave very different compass readings when using the same app, at the same time, in the same location.

Even among more established brands, discrepancies are common. For example, the iPhone 12 Pro Max and iPhone 16 Pro sometimes differed in orientation by just a few degrees despite running the same app and being calibrated minutes earlier.

Perhaps most telling is that devices rarely provide the same reading twice in a row with absolute consistency. Changes like moving the phone a few feet or switching to a different compass app often result in significantly different results.

This inconsistency highlights a key problem: Smartphone compasses are inherently unstable. They’re designed for quick, general orientation, not precise or reliable navigation.

If two nearly identical phones can give you completely different directions in the same place, then it's clear that relying solely on a digital compass is a bit of a gamble.

What does this mean for navigation?

You might be thinking, “I use Google Maps, so why does this matter?” That’s a fair question. Navigation apps rely on GPS, motion sensors, and compass directions to determine your location and direction. The compass becomes especially important when you’re standing still.

If you’ve ever opened Maps and noticed the blue dot spinning erratically, chances are your compass is having trouble determining direction. Luckily, GPS data usually takes over when you start walking. But if you’re trying to orient yourself before you set off, especially in an unfamiliar area, you’re relying on a tool that may not be working properly.

The problem is more pronounced in urban environments. Tall buildings, underground transportation, and metal objects all contribute to electromagnetic interference. It’s not uncommon for your phone to tell you’re facing west when you’re looking directly at the sunrise.

Things you can do to improve accuracy

The good news is that compass accuracy can often be improved. Making slow, deliberate figure-eight motions on a non-metallic surface can sometimes help significantly.

On Android devices, you can find the "Calibrate Compass" option in your location settings. For iPhones, opening the Compass app and slowly rotating your device in a horizontal circle may help. In some cases, a reboot will do the trick.

Surprisingly, removing the phone from its magnetic case can sometimes immediately improve accuracy. The Motorola Edge 2023 that I struggled with for hours worked just fine after removing the case.

Additionally, you can take steps to simplify your phone to reduce interference. Taking these steps can potentially improve compass accuracy and optimize your device for better performance.

However, even under ideal conditions, a phone compass cannot match the reliability of a traditional compass. This is especially important to remember when using a compass indoors or in environments with a lot of interference.

Don't rely on your phone's compass in critical situations.

Imagine you’re hiking in an area with limited GPS coverage. You pull out your phone, open the compass app, and expect it to guide you. There’s a chance it will work, or it could lead you further astray.

This is not a conspiracy theory of alarm. The danger lies not in the tool itself, but in the false sense of confidence it can give. It is easy to go astray when you have a faulty tool to guide you.

Don’t rely solely on your smartphone in critical situations where accurate navigation is essential. Make sure you carry a real compass and learn how to use it properly. Your phone should be a backup, not your primary navigational aid.

A compass on your phone can be convenient, but it’s not perfect. While it’s generally adequate for general use, it’s not reliable in situations where accuracy really matters. If you’re navigating off the grid, exploring unfamiliar terrain, or otherwise relying on precise direction, your phone should be a secondary tool, not your sole tool.

Know how your device works, understand its quirks, and most importantly, carry a real compass when needed. Ultimately, the convenience of digital is no substitute for the reliability of a dedicated device.