A short, curated guide — not an automatic related dump. Figures come from SubMouse's safe-for-work directory when we have them.
r/math (about 4M members, directory rank #239) is for discussion of mathematics. Everyday “they did the math” applications, physics and broader science news each fit better when the thread is not mathematics itself.
Stay on math for mathematics discussion. Use theydidthemath for applied numerical takes on real-world claims, Physics for physics study and research talk, and science for multi-field research news.
r/math — math
This subreddit is for discussion of mathematics. All posts and comments should be directly related to mathematics, including topics related to the practice, profession and community of mathematics.
Useless Yet Interesting Calculations
When to choose it: Real-world claims checked with calculations.
Why it is here: Public description: And they said math has no real world applications (about 2.5M members, rank #456). Listed with math in related neighbourhoods.
How it differs from r/math: Applied curiosity math versus mathematics as a field.
Physics
When to choose it: Physics students and researchers rather than pure math.
Why it is here: Public description: For physicists and physics students. See the rules before posting, and the subreddit wiki for common questions. Basic homework questions are not allowed. (about 3.3M members, rank #320).
How it differs from r/math: Physics remit versus mathematics discussion.
Reddit Science
When to choose it: Broader scientific research across fields.
Why it is here: Public description: This community is a place to share and discuss new scientific research. Read about the latest advances in astronomy, biology, medicine, physics, social science, and more. Find and (about 34.6M members, rank #11).
How it differs from r/math: Multi-field science news versus math-focused talk.
Run the automatic finder for r/math (results are matched from our directory; that page is not indexed): Find related to r/math.
Members and public descriptions come from SubMouse's safe-for-work directory (as of 2026-11-02 UTC); 7-day growth measured from 2026-10-26. Posts/day and culture claims appear only when we have them — missing fields stay n/a. Directory rank is listing order. Communities outside the published Top 100 open in the info tool instead of a full community page. Guide updated 2026-11-07.