Bubble Level

Bubble Level turns your phone into a practical spirit level for everyday checks — hanging a picture, leveling a shelf, checking a floor, or helping an appliance sit level.

MEASUREMENT MODES
• Level Mode — place the edge of your phone against a surface to check horizontal alignment.
• Plumb Mode — place the edge of your phone against a wall, post, or frame to check vertical alignment.
• Flat Mode — place the front or back of the phone on a surface to measure tilt across two axes.
• Camera Mode — view adjustable alignment guidelines over the live camera preview (Pro).

WHERE IT HELPS
• Hanging pictures, mirrors, and shelves straight.
• Checking whether furniture and appliances are level.
• Checking walls, door frames, and posts for vertical alignment.
• Getting a rough indication of floor, terrace, or walkway slope.

FREE — INCLUDED FOR EVERYONE
• Level, Plumb, and Flat modes.
• Angle readings in degrees.
• Visual alerts with an adjustable range and color.
• Vibration alerts.
• Optional alerts at multiples of 45°.
• Selectable reference edges and automatic reference selection.
• Press-and-hold lock to freeze a reading.
• Guided calibration with one calibration profile.
• Warnings for incomplete calibration or low sensor accuracy.
• Up to 3 saved measurements, with copy and share.
• Dark theme, keep-screen-on option, and decimal display settings.
• Available in many languages.

PRO — ONE-TIME PAYMENT, NO SUBSCRIPTION
• Camera Mode with adjustable live guidelines.
• Additional units: percent, in/ft, and mm/m.
• Sound alerts.
• Button lock and 5-second delayed lock.
• Two additional calibration profiles for different case setups.
• Unlimited saved measurements.
• Custom theme color.

PRIVACY
• No ads, accounts, sign-up, or tracking.
• Measurements are stored on your device. The app does not send them to its own servers.
• If Android backup is enabled, measurements may be included in your device backup.
• Camera Mode runs entirely on your device. The app does not upload anything from the camera.

CALIBRATION
The guided calibration wizard covers six orientations: back, front, bottom, top, left, and right. Calibration corrects the constant offset caused by sensor alignment and the shape of the device. You do not need a perfectly level reference surface.

ACCURACY AND LIMITS
This app is a practical aid, not a certified measuring instrument. Readings depend on the device, conditions, and calibration. Calibration can correct constant offset but cannot eliminate sensor noise or scale errors that grow with angle. Camera Mode shows the tilt of your device, not the true geometry of objects in the image.

Do not rely on this app alone for professional work, structural assessments, or safety-critical decisions. Use an appropriate measuring instrument and consult a qualified professional when necessary.