Bubble
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.
- Android
- Java
- Education & language
- Actively maintained
About Bubble
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.
Privacy and F-Droid
F-Droid builds Bubble from its published source code and flags anti-features such as ads, tracking or reliance on non-free services.
No anti-features flagged on the latest F-Droid build.
Screenshots
Screenshots from the app's F-Droid listing.
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What is Bubble?
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.
Is Bubble free and open source?
Yes. Bubble's source code is public on GitHub under the GPL-3.0-or-later license, which is OSI-approved or FSF-free. F-Droid, which builds it from source, flags no anti-features such as ads or tracking on its latest build.
How do I install Bubble?
You can install Bubble from F-Droid (package org.woheller69.level); the links are on this page. Its GitHub repository also publishes releases (latest: V3.5).
Is Bubble still maintained?
The repository's most recent commit was on Aug 15, 2026. Its F-Droid listing was last updated on Aug 14, 2026. appsgit only lists apps whose repository had a commit in the last six months.