Smart Level Tool: Bubble Level

Smart Level Tool turns your phone into a bubble level using its motion sensor (accelerometer).

• Surface: a bullseye level for tabletops, shelves and floors, with a live reading for both axes.
• Edge: a single-axis level for a phone stood on its edge, for checking a wall, frame or post — tells you when it is plumb (vertical) or level (horizontal).
• Choose your units: degrees, percent grade, millimetres per metre, or roof pitch.
• Zero the reading on a reference surface, or use a two-point zero to cancel the surface's own slope. Save a zero as a named profile to reuse it.
• Hold a reading, name it and save it. Set a saved reading as a target to match a second surface or wall to the first, within your chosen tolerance.
• The phone vibrates once when level (you can turn this off), or play a tone instead.
• Set your own level tolerance and choose a Balanced or Responsive sensor rate.
• Light and dark themes. Portrait, landscape and tablet layouts.

Good to know
• Accuracy depends on your phone's own sensor and shape: a case or a camera bump can tilt it. Zero the app on a surface you know is level, and check against a physical spirit level for work that must be exact.
• No account is needed. Readings, zero settings and saved items stay on your phone.
• Works without an internet connection.

Recent changes:
Smart Level Tool has been rebuilt.

• New Edge tab: a plumb/level check for a phone stood on its edge.
• True degree readings, plus percent grade, mm/m and roof pitch units.
• Zero is now kept between app launches, and can be saved as a named profile.
• Hold and save readings, and match a second surface or wall to a saved one.
• New settings for tolerance, sensor rate, and vibration/tone feedback.