What Is a Device Motion Test?
This tool reads your device's real accelerometer and gyroscope data live, using the standard
DeviceMotionEvent API. It reports three distinct sets of genuine sensor values: raw
acceleration from your own movement, acceleration including the constant pull of gravity, and rotation rate
from the gyroscope - all updating continuously and reflecting exactly what your device's physical motion
sensors are measuring.
How to Use the Device Motion Test
- On iOS, tap "Enable Motion Sensors" and grant permission when prompted.
- Hold your device still on a flat surface and note the "Acceleration Including Gravity" values - one axis should read close to 9.8, matching Earth's gravitational pull.
- Pick the device up and shake it gently - watch "Acceleration" (without gravity) respond to your actual movement.
- Rotate the device around different axes and watch the "Rotation Rate" values respond to gyroscope input.
How It Works
The devicemotion event fires continuously and provides three separate data sets. The
acceleration property reports movement with gravity's constant effect filtered out where the
device supports that separation, useful for detecting genuine motion like shaking or tilting quickly. The
accelerationIncludingGravity property reports the raw combined value, which is why a
stationary device still shows a nonzero reading - Earth's gravity constantly pulls at roughly 9.8 m/s² along
whichever axis currently points downward. The rotationRate property comes from the gyroscope
and reports how quickly the device is rotating around each axis, in degrees per second.
Understanding Your Results
- One gravity-inclusive axis reads close to 9.8 while stationary - expected and correct; this confirms your accelerometer is properly detecting Earth's gravitational pull.
- Acceleration (without gravity) stays near zero while still, then spikes when shaken - your device's motion sensors are distinguishing real movement from the constant gravity baseline correctly.
- Rotation rate values respond promptly and return near zero when you stop rotating - your gyroscope is tracking rotational movement accurately.
- All values show " - " or never update - your device likely lacks the relevant motion sensor hardware, or your browser doesn't currently support exposing that particular data.
Browser Limitations
Motion sensors are a mobile and tablet feature - most desktop and laptop computers don't have an accelerometer or gyroscope at all, so testing on a desktop will typically show no data, which reflects the hardware rather than a fault in this test. iOS requires an explicit permission grant through a user gesture before any motion data becomes available. Not every device separates true acceleration from gravity equally well; on some hardware, the "acceleration" value (gravity excluded) may be less precise than "acceleration including gravity."
Common Mistakes to Avoid
- Testing on a desktop and expecting live data - desktops and most laptops lack the motion sensors this test reads from.
- Denying the iOS permission prompt - without granting it, no motion data can be read on iOS 13 and later.
- Confusing gravity-inclusive acceleration with actual movement - the gravity-inclusive reading stays high even when perfectly still, which is expected and not a fault.
Frequently Asked Questions
Why does "Acceleration Including Gravity" show a value even when my device is perfectly still?
Earth's gravity constantly pulls on the accelerometer at roughly 9.8 m/s², so a stationary device will always show this baseline value along whichever axis is currently pointing downward - this is expected physics, not a sensor error.
What's the difference between the accelerometer and gyroscope readings?
The accelerometer measures linear movement and gravity along three axes; the gyroscope measures rotational speed around those same three axes - they capture different, complementary kinds of motion.
Why does this show no data on my laptop?
Most desktop and laptop computers don't include accelerometer or gyroscope hardware, so no motion data is available to report - this is a hardware limitation, not a test fault.
Is my motion data stored or sent anywhere?
No. All motion sensor data is read and displayed live in your browser only, for the current session, and is never transmitted or saved.
Why do I need special permission on iPhone but not Android?
iOS 13 and later require an explicit user gesture and permission grant before any website can access motion sensor data, as a privacy protection; this specific requirement isn't part of the standard on other platforms.
Conclusion
Whether you're confirming your device's accelerometer and gyroscope are functioning, or just curious how motion sensors actually report data, this gives you a real, live reading straight from the hardware. For tilt and compass-specific data, check the Orientation Sensor Test.