About r/Physics
In its own words:
For physicists and physics students. See the rules before posting, and the subreddit wiki for common questions. Basic homework questions are not allowed.
Community guide
r/Physics (#320, about 3.3 million) is for physicists and physics students—see wiki for common questions; basic homework not allowed. Rules: no homework, unscientific content, sensational titles, meme/image posts, or duplicates; use weekly threads. Text/Image (~20.1 ppd).
Physics Q&A without homework dumps
Student/physicist discussion fits; basic homework questions are removed.
No memes; use weeklies
No meme/image posts or sensational titles; prefer weekly threads when directed.
Practical pointers
Text-leaning samples; Question flair common.
SubMouse Editorial
The community was created on Mar 16, 2008, which makes it 18 years old. Since Oct 26, 2026, it has gained 1,079 subscribers (+0.03%). It sits just behind r/cursedcomments (#319) and ahead of r/Perfectfit (#321) in our ranking.
What sets r/Physics apart
r/Physics is far more text-driven than most big subreddits: 69% of its recent posts are text posts, against a median of 34% across the Top 100. Its rhythm is strongly tied to time zones: the busiest hour (12:00 UTC) sees about 4.5× as many posts as the quietest (03:00 UTC).
Subscriber growth
Between Sep 19, 2026 and Nov 2, 2026, r/Physics went up from 3,247,240 to 3,254,652 subscribers (+7.4K, +0.23%). That is about 168 new members per day. The chart uses our weekly snapshots (9 so far), so it gets longer every week.
What r/Physics talks about
Across 129 recent posts (Oct 29–Nov 5), the words that come up most are “help”, “theory”, “quantum”, “question” and “questions”. Other frequent themes are earth, confused, energy, dark, matter and decay. Recurring phrases include “weekly discussion”, “string theory”, “high school” and “dark matter”. By format, 69% are text posts, 11% are images and 10% are links.
Popular post flairs: Question (32), Image (14), Video (6), Meta (3), News (2).
Activity and best time to post
r/Physics gets about 20 new posts a day. The public archive holds 188,352 posts and 1,578,312 comments in total, about 8.4 comments per post. Last week the busiest day was Friday (22 posts) and the quietest was Wednesday (14). Posting peaks around 12:00 UTC and is lowest around 03:00 UTC.
Rules of r/Physics
The moderators of r/Physics list 6 rules. In short:
- No homework questions
- No unscientific content
- No sensationalist titles
- No meme/image posts
- No duplicate posts
- Use weekly threads
How to join
Open reddit.com/r/Physics and press “Join”. Read the community rules in the sidebar before you post: every subreddit is run by its own volunteer moderators.
Frequently asked questions
How big is r/Physics?
r/Physics has 3,254,652 subscribers (Nov 2, 2026), which makes it the #320 safe-for-work subreddit in the SubMouse ranking. It added 7,412 members between Sep 19, 2026 and Nov 2, 2026.
How old is r/Physics?
r/Physics was created on Mar 16, 2008, so it has been around for 18 years.
How active is r/Physics?
Very active: r/Physics gets about 20 new posts a day (average of the last four weeks). Over its lifetime the archive counts 188,352 posts and 1,578,312 comments. In a sample of 129 recent posts we counted 119 different authors.
When is r/Physics most active?
Based on post counts from Oct 29, 2026 to Nov 4, 2026, the busiest day was Friday and the quietest Wednesday, and most posts arrive around 12:00 UTC, with the fewest around 03:00 UTC. More posts also means more competition, so a quieter hour can help a post get noticed.
What is r/Physics about?
The community describes itself as: “For physicists and physics students. See the rules before posting, and the subreddit wiki for common questions. Basic homework questions are not allowed.” Recent post titles often mention help, theory, quantum, question and questions. Most posts are text posts (69%).
Is r/Physics safe for work?
Yes. Reddit does not mark r/Physics as an 18+ (NSFW) community. SubMouse lists safe-for-work subreddits only.
How do I post on r/Physics?
Join the community on Reddit first, then use “Create post”. r/Physics accepts both text and link posts, with images, galleries and polls enabled. It has 6 posted rules, starting with: “No homework questions”; “No unscientific content”; “No sensationalist titles”. Moderators remove posts that break the rules, so read them in the sidebar before posting.
Which communities are like r/Physics?
Communities with similar topics include r/science (34.6M), r/Fitness (12.6M), r/Boxing (3.2M), r/lifehacks (14.6M) and r/DestinyTheGame (3.4M).
Stats from public data (data updated Nov 2, 2026; activity, rules and archive totals via the Arctic Shift archive, Nov 6, 2026). Point and comment counts are archive snapshots and can be lower than on Reddit today. SubMouse is an independent directory and is not affiliated with Reddit or the moderators of r/Physics.