Accelerometer Test

How to test your accelerometer

1. Open this page on your phone or tablet.

   An accelerometer test needs real motion sensor hardware, which desktop computers don't have.

2. Tap "Start test."

   On iPhone, you'll see a permission prompt — tap Allow. Android usually starts immediately.

3. Move your device left and right, then up and down.

   Watch the ball and the X/Y readings track the direction, one axis at a time for the clearest result.

4. Don't worry about the rebound.

   A small bounce-back right after you stop moving is completely normal — that's the sensor correctly detecting deceleration.

5. Give it a firm shake.

   Check that the shake counter increases and the dot on the G-force diagram jumps outward.

Who tests an accelerometer, and why

Buyers checking a second-hand phone run this before handing over payment, since a faulty accelerometer quietly breaks step counting, shake gestures, and plenty of motion-based games without necessarily throwing an obvious error. People troubleshooting an inaccurate step counter or fitness tracker run it to confirm whether the raw sensor is actually working before assuming a software or calibration problem. App and game developers use it to check that shake-to-undo, motion controls, or fall-detection features respond correctly across different hardware. And after a drop or a repair, this is usually the fastest way to confirm the motion sensor itself survived intact.

Understanding the X, Y, and Z axes

An accelerometer measures acceleration along three axes at once, each corresponding to a direction relative to the device itself rather than the room around it.

G-force is a simple way of expressing total acceleration relative to Earth's gravity — 1G equals 9.81 m/s², the acceleration gravity applies to everything at rest. The diagram above works like the "friction circle" used in motorsport telemetry: the dot's distance from the centre is your current G-force, its direction shows which way the force is pushing, and the fading trail behind it traces your recent movement. A stationary phone sits close to the first ring (1G), moderate movement pushes the dot toward the second ring, and a firm shake can briefly send it well past that — the dashed marker stays behind to mark the peak you've reached.

Why you see gravity at rest, and why motion rebounds

If your phone is sitting perfectly still and the gauge still shows roughly 1G, that's not a bug — it's Earth's gravity, and every accelerometer on the planet detects it constantly regardless of whether the device is moving. Seeing a non-zero reading at rest is actually a good sign your sensor is working; a reading stuck at exactly zero while stationary would be more suspicious.

You may also notice the ball or the readings seem to "rebound" in the opposite direction right after you stop moving the phone. That's expected too: an accelerometer measures acceleration, not position, and stopping a moving object is itself a deceleration — which reads as acceleration in the reverse direction. Move the phone right, and you'll see a brief acceleration to the right followed by a brief one to the left as it comes to a stop. Both parts are the sensor doing its job correctly.

Accelerometer problems at a glance

Accelerometer vs. gyroscope

These two sensors get confused constantly because phones use them together, but they answer different questions. An accelerometer measures linear acceleration and force — is the device moving, shaking, falling, or sitting still under gravity. A gyroscope measures rotation — is the device spinning or tilting around its own centre, independent of whether it's also moving through space.

A simple way to remember it: shaking a phone in your hand mostly triggers the accelerometer; spinning it in place mostly triggers the gyroscope. Most real motion — walking, turning a corner, tilting to steer in a game — involves a mix of both, which is exactly why phones combine their data rather than relying on either alone. If you want to test rotation specifically, our Gyroscope Test covers that in detail.

Real-world uses for a phone's accelerometer

How the sensor itself works

Most phone accelerometers today are MEMS devices — micro-electromechanical systems — built as a tiny mechanical structure etched directly onto a silicon chip, small enough that dozens could fit on a fingernail. Inside, a microscopic mass is suspended by springs so small they're barely visible even under magnification. When the phone accelerates in any direction, that tiny mass lags behind for a fraction of a second due to inertia, flexing the springs supporting it. The chip measures that flex electrically and converts it into the X, Y, and Z readings this page displays.

This is also why accelerometers are genuinely cheap and durable enough to put in nearly every phone, smartwatch, and fitness tracker made today — there are no moving parts in the everyday sense, no lubrication to dry out, and no bearings to wear down, just a solid-state structure flexing by microscopic amounts thousands of times a second.

More tools on ProDeviceTest

Troubleshooting a whole device rather than just the accelerometer? These run the same way — instant, no download, right in your browser.

• Gyroscope Test — check rotation with a live 3D phone and compass
• Vibration Test — check your phone's vibration motor
• Touch Screen Test — check every part of your screen for dead zones
• Webcam Test — verify your camera before a call
• All Mobile Tests — the full category