# Bubble (open-source education app)

> Bubble is a free, open-source education app for Android. Spirit level and ruler. It has 376 GitHub stars and is released under the GPL-3.0-or-later license, and you can install it from F-Droid.

With Bubble you can measure angles and inclination. Simply align one of your phone's four sides with an object or place it on a level surface to determine its orientation. A ruler in cm and inches is also available. Experience a user-friendly and ad-free solution with no permissions required.

## Key facts

| Fact | Value |
|---|---|
| Repository | https://github.com/woheller69/Level |
| Platforms | Android |
| Built with | Java |
| GitHub stars | 376 |
| License | GPL-3.0-or-later (open source) |
| F-Droid | https://f-droid.org/packages/org.woheller69.level/ (package org.woheller69.level) |
| F-Droid anti-features | none flagged |
| Google Play | not linked |
| App Store | not linked |
| Website | none listed |
| Official | no |
| Category | Education & language |
| Latest release | V3.5 (Aug 12, 2026) |
| Last commit | Aug 15, 2026 |

F-Droid builds its apps from source and flags anti-features: https://f-droid.org/en/docs/Anti-Features/

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