How to use the online spirit level
- Open this page on your phone. On iPhone and iPad, tap Start level and allow motion access; Android phones start straight away.
- Flat mode: lay the phone on its back on a shelf, table or appliance. Centre the bubble in the small ring; the readout shows the total tilt and the left–right and front–back angles.
- Edge mode: stand the phone on its long or short edge against a picture frame, shelf or door frame. The vial shows which side is high and by how many degrees.
- The screen turns green and the phone vibrates briefly when the surface is level (within 0.3°). Use Hold reading to freeze the number when you cannot see the screen.
Calibrate for better accuracy
Phone sensors are accurate to roughly 0.1–0.5°, but the camera bump and case can tilt the phone when it lies on its back. To calibrate, place the phone on a surface you know is level (or check one spot, turn the phone 180° on the same spot and use the average), then tap Calibrate. The offset is saved on this device. Remove a thick case or camera bump problem by measuring on the phone's edge instead.
For context, a slope of 1° is about 1.7 cm per metre (or 3/16 inch per foot). That is enough to make a shelf look crooked or a fridge door swing shut, but a gentle fall of about 1–2% (0.6–1.1°) is intentional on patios, gutters and shower floors so that water drains away. For long spans such as worktops or decking, use the phone on a straight piece of timber to average out bumps, or check with a traditional spirit level.
The page reads the orientation sensor through your browser; nothing is recorded or sent anywhere.
How accurate is a phone spirit level?
Usually within about 0.1–0.5° after calibration, which is good enough for pictures, shelves, furniture and appliances.
Why does it say no sensor detected?
Laptops and desktops rarely have a tilt sensor. Open the page on a phone or tablet. Some browsers also block motion sensors on insecure pages or in private modes.
How do I level a picture frame?
Switch to Edge mode, rest the phone's long edge on top of the frame and adjust until the screen turns green.
What does 1 degree of slope mean?
About 17.5 mm per metre, or roughly 3/16 inch per foot (a 1.75% slope).