About this tool
This spirit level turns your smartphone into an inclinometer – right in the browser, no app needed. It reads your device’s orientation sensor and detects how you hold it: lying flat, a round bubble shows the tilt in both directions. Standing on an edge, a line shows the horizontal and the value shows the deviation from the nearest right angle – handy for shelves, picture frames or door frames.
The tilt is shown in degrees and as a slope in percent, as used for ramps, patios or drain pipes. Cases and camera bumps skew the result; “Set zero” compensates for that. The calibration is stored only in your browser. More measuring tools for your phone are the Compass and the Height Meter.
How it works
- Open the page on your smartphone and tap “Start spirit level”. On an iPhone, allow access to “Motion & Orientation”.
- Lay the phone flat on the surface or hold one of its edges against the workpiece.
- Adjust the workpiece until the display turns green. “Hold” freezes the value so you can read it.
Frequently asked questions
How accurate is the phone spirit level?
Smartphone sensors resolve about 0.1°; the display is smoothed and counts as level below 0.5°. Without calibration, the housing, a case or the camera bump can add several tenths of a degree. For precise work, calibrate once on a surface you know is level, or measure, turn the phone by 180° and take the average.
Why do I have to allow access on an iPhone?
Since iOS 13, websites may only use the motion and orientation sensors after a permission prompt, which appears when you tap “Start”. If you declined it, close the tab, open the page again and allow access on the next start.
What does the percentage mean?
Percent is the slope: rise divided by run, times 100. 1 % means 1 cm of height difference over 1 m, 100 % equals 45°. Drain pipes, for example, usually need a slope of 1 to 2 %.
Does the spirit level work on a computer?
No, laptops and desktop PCs usually have no orientation sensor. On a computer the page shows a QR code that opens it right on your phone. Tablets with an orientation sensor work just like smartphones.
Are my sensor readings stored or sent anywhere?
No. The readings are processed only in the browser. Only the calibration zero point is stored locally in your browser so you don’t have to set it again next time.