How the physics communities compare
Membership is concentrated: the three largest communities hold 96% of all members on this list, so most of the physics conversation happens in a handful of places. Size and activity don't line up perfectly: r/Physics has the most members, but r/AskPhysics gets the most new posts (about 42 a day, against 22 in r/Physics). Per member, the liveliest is r/TheoreticalPhysics: 2.9 posts a day from 31.2K members — a smaller crowd, but an engaged one. Among the communities we track weekly, r/AskPhysics grew fastest recently (+0.06%, +966 members since Oct 26). The oldest is r/Physics, founded in 2008, and every community here is more than five years old — this is a long-established corner of Reddit.
The 7 biggest physics subreddits
r/Physics 3,254,059 members · ~22 posts/day · +1.1K since Oct 26 · since 2008For physicists and physics students. See the rules before posting, and the subreddit wiki for common questions. Basic homework questions are not allowed.
r/AskPhysics 1,575,014 members · ~42 posts/day · +966 since Oct 26 · since 2011Ask Physics
- Pr/physicsgifs ↗ 216,235 members · since 2012
GIFs that show physics principles at work in the real world or in a simulation.
- Pr/PhysicsStudents ↗ 105,078 members · since 2013
A place for physics students of any level to discuss the intricate profoundness of the universe.
- Qr/QuantumPhysics ↗ 57,222 members · ~1.4 posts/day · since 2011
A subreddit for discussing all things related to quantum mechanics.
- Pr/ParticlePhysics ↗ 34,222 members · ~0.7 posts/day · since 2009
All about particle physics.
- Tr/TheoreticalPhysics ↗ 31,195 members · ~2.9 posts/day · since 2012
Post and discuss external content related to advanced research in physics. Remember to always back up your posts with reliable information, clear argumentation and verifiable sources. Professional or amateur self-theories and mod…
Choosing where to post
Questions do best in r/AskPhysics, the community on this list that is built around advice and help (around 42 posts a day).
A simple rule of thumb: ask questions in the specialised communities and share your best finds in the big ones, where they can reach the most people. Always read the rules in the sidebar first — each community is run by its own volunteer moderators. Our guide to searching Reddit explains how to dig through any of these communities, and the subreddit info tool gives you the stats of one we don't list.
Frequently asked questions
Which physics subreddit has the most members?
r/Physics is the largest, with 3,254,059 members, followed by r/AskPhysics (1.6M) and r/physicsgifs (216.2K).
Where are the most new physics posts?
By new posts per day, r/AskPhysics leads with about 42, ahead of r/Physics (22). Counts are averages over the last seven days.
Which physics subreddit is best for questions?
r/AskPhysics is the one built around questions and advice, with about 42 new posts a day. Check its rules and search it first — common questions have usually been answered.
How many physics communities are on this list?
We list 7 active, safe-for-work physics communities with at least 25,000 members each, 5.3M members in total (people can be in several). Reddit has many smaller ones too; our guide on searching Reddit shows how to find them.
What is the oldest physics subreddit?
r/Physics, created on Mar 16, 2008.
Are these physics subreddits safe for work?
Yes. Every community on this page is public and not marked 18+ by Reddit, and we filter out communities whose name or description points to adult content.
Data: Reddit's public subreddit search and the Arctic Shift archive (Nov 6, 2026), growth from SubMouse's weekly snapshots. Member counts of communities outside our Top 1000 come from the archive and can lag a little. Not affiliated with Reddit.