About r/chemistry
In its own words:
A community for chemists and those who love chemistry
Community guide
r/chemistry (#252, about 3.9 million) is for chemists and chemistry enthusiasts. Rules redirect classwork/homework/exam/lab questions, constrain undergrad/HS help patterns, ban nefarious synthesis talk, jerks, unmarked NSFW, zero-content posts, ChatGPT/AI chemistry dumps, medical advice, and push routine asks into megathreads. Text/Image (~29 ppd).
Chemists’ room, not homework dump
Homework/exam/lab classwork is restricted; use megathreads where required.
Safety and AI limits
No nefarious-deed guidance; no medical advice; AI/ChatGPT chemistry content is policed.
Practical pointers
Skip zero-content posts; text/image/link mix in samples.
SubMouse Editorial
The community was created on Mar 13, 2008, which makes it 18 years old. Since Oct 26, 2026, it has gained 890 subscribers (+0.02%). It sits just behind r/comics (#251) and ahead of r/reactiongifs (#253) in our ranking.
What sets r/chemistry apart
Its rhythm is strongly tied to time zones: the busiest hour (18:00 UTC) sees about 8.0× as many posts as the quietest (09:00 UTC).
Subscriber growth
Between Sep 19, 2026 and Nov 2, 2026, r/chemistry climbed from 3,881,707 to 3,887,915 subscribers (+6.2K, +0.16%). That is about 141 new members per day. The chart uses our weekly snapshots (9 so far), so it gets longer every week.
What r/chemistry talks about
We read the titles of 182 recent posts (Oct 29–Nov 4), the words that come up most are “help”, “advice”, “water”, “molecular” and “questions”. Other frequent themes are chemical, lab, organic, research, looking and light. Recurring phrases include “extracting starch”, “white phosphorus”, “open source” and “gc-ms reaction”. By format, 53% are text posts, 17% are images and 15% are links.
Activity and best time to post
r/chemistry gets about 29 new posts a day. The public archive holds 222,752 posts and 2,015,227 comments in total, about 9.0 comments per post. Last week the busiest day was Monday (32 posts) and the quietest was Sunday (18). Posting peaks around 18:00 UTC and is lowest around 09:00 UTC.
Rules of r/chemistry
The moderators of r/chemistry list 9 rules. In short:
- Classwork, Homework, Exam, And Lab Questions
- Undergraduate and High School Chemistry
- Nefarious deeds
- Being a Jerk
- NSFW
- Zero-content material
- ChatGPT and AI Chemistry
- Medical advice
- Use appropriate Megathreads
How to join
Open reddit.com/r/chemistry 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 many members does r/chemistry have?
r/chemistry has 3,887,915 subscribers (Nov 2, 2026), which makes it the #252 safe-for-work subreddit in the SubMouse ranking. It added 6,208 members between Sep 19, 2026 and Nov 2, 2026.
How old is r/chemistry?
r/chemistry was created on Mar 13, 2008, so it has been around for 18 years. The oldest post in the public archive is from Mar 14, 2008.
How active is r/chemistry?
Very active: r/chemistry gets about 29 new posts a day (average of the last four weeks). Over its lifetime the archive counts 222,752 posts and 2,015,227 comments. In a sample of 182 recent posts we counted 166 different authors.
When is r/chemistry most active?
Based on post counts from Oct 29, 2026 to Nov 4, 2026, the busiest day was Monday and the quietest Sunday, and most posts arrive around 18:00 UTC, with the fewest around 09:00 UTC. More posts also means more competition, so a quieter hour can help a post get noticed.
What is r/chemistry about?
The community describes itself as: “A community for chemists and those who love chemistry” Recent post titles often mention help, advice, water, molecular and questions. Most posts are text posts (53%).
Is r/chemistry safe for work?
Yes. Reddit does not mark r/chemistry as an 18+ (NSFW) community, and its own rules forbid NSFW content. SubMouse lists safe-for-work subreddits only.
How do I post on r/chemistry?
Join the community on Reddit first, then use “Create post”. r/chemistry accepts both text and link posts, with images, videos and galleries enabled. It has 9 posted rules, starting with: “Classwork, Homework, Exam, And Lab Questions”; “Undergraduate and High School Chemistry”; “Nefarious deeds”. Moderators remove posts that break the rules, so read them in the sidebar before posting.
Which communities are like r/chemistry?
Communities with similar topics include r/DestinyTheGame (3.4M), r/videos (26.9M), r/MinecraftMemes (3.4M), r/TravelHacks (5.8M) and r/homestead (3.6M).
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/chemistry.