Spirit level for your phone
Tap “Start level” and place the phone on the surface – the bubble shows which side is lower. Held upright against an edge, it becomes a tube level for shelves and pictures.
How it is calculated
How to use the spirit level
- Tap “Start level” (on iPhone, confirm the permission for motion and orientation).
- Lay it flat: the round bubble shows the tilt in both directions. Like a real level, the bubble moves to the higher side.
- Hold it upright against an edge: the display switches to a tube level and shows how far the bottom edge deviates, in degrees and as a slope in percent.
- Below 0.3° deviation the frame turns green: level.
Calibrating
Phone sensors often have a small zero error, and some phones rock because of the camera bump. Place the phone on a surface you know is level and tap “Set to zero” – the zero point is stored in this browser. Tip: afterwards turn the phone 180°. If it then shows twice the error, the surface was not level.
How it measures
The browser reports the orientation according to the W3C DeviceOrientation specification. From this the tool calculates the direction of gravity relative to the screen and from that the tilt – the same principle as tilt sensing with accelerometers. The slope in percent is tan(angle) × 100; 1° is about 1.75 %.
Limits
- Accuracy depends on the device’s sensor and is not guaranteed – for masonry or precision work, use a real spirit level.
- The measurement refers to the phone’s housing. Camera bumps and cases distort the result, so calibrate.
Frequently asked questions
How do I use my phone as a spirit level?
Open the page, tap “Start level” and place the phone on the surface or hold it upright against an edge. The bubble shows the tilt.
How accurate is a phone spirit level?
It depends on the sensor; after calibration it is often good enough for shelves, pictures and furniture. For construction a real level is more accurate.
How do I calibrate the level?
Place the phone on a surface you know is level and tap “Set to zero”. The zero point stays stored in this browser.
What does slope in percent mean?
Height difference per 100 units of length: 2 % is 2 cm over 1 m. Mathematically tan(angle) × 100, about 1.75 % per degree.
Why does it not work on my laptop?
Most laptops and PCs have no orientation sensor. Open the page on a phone or tablet.
Sources and legal basis
- W3C – DeviceOrientation Event Specification
- MDN Web Docs – DeviceOrientationEvent
- MDN Web Docs – DeviceOrientationEvent.requestPermission() (iOS)
As of:
Related tools
- Online protractorOnline protractor: measure an angle on your screen with three points, or get your phone’s tilt angle from its sensor, in degrees and percent. No app needed.
- Online compass for your phoneFree online compass, no app needed: shows your direction using your phone’s orientation sensor, magnetic or true north with declination. Nothing is sent.
- Online ruler in actual sizeOnline ruler for your phone or screen: calibrate once with a bank card, then measure in cm, mm or inches at real size. Free, no app and no sign-up.
- Altimeter: how high am I?Online altimeter: shows your phone’s GPS altitude with accuracy, average, minimum and maximum, in metres or feet, with a note on ellipsoid vs. sea level.
- Classroom noise meter traffic lightNoise traffic light in your browser: the microphone measures loudness and the light turns green, yellow or red. Adjustable thresholds, full screen. Free.
- CPS Test: How Many Clicks Per Second Can You Do?Free CPS test: measure your clicks per second over 1, 5, 10 or 60 seconds and track your best score per duration. Works with mouse, touchpad and touch.