How the science communities compare
Membership is concentrated: the three largest communities hold 87% of all members on this list, so most of the science conversation happens in a handful of places. Size and activity don't line up perfectly: r/science has the most members, but r/askscience gets the most new posts (about 193 a day, against 38 in r/science). Among the communities we track weekly, r/psychology grew fastest recently (+0.06%, +2.9K members since Oct 19). The oldest is r/science, founded in 2006, and every community here is more than five years old — this is a long-established corner of Reddit.
The 6 biggest science subreddits
r/science 34,575,992 members · ~38 posts/day · +6.9K since Oct 19 · since 2006This 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 submit new publications and popular science cover…
r/space 27,990,867 members · ~26 posts/day · +3.9K since Oct 19 · since 2008Share & discuss informative content on: * Astrophysics * Cosmology * Space Exploration * Planetary Science * Astrobiology
r/askscience 26,381,450 members · ~193 posts/day · +3.9K since Oct 19 · since 2008Ask a science question, get a science answer.
r/psychology 4,920,808 members · ~17 posts/day · +2.9K since Oct 19 · since 2008A Reddit community for sharing and discussing science-based psychological material.
r/compsci 3,996,894 members · ~5.0 posts/day · +550 since Oct 19 · since 2008Computer Science Theory and Application. We share and discuss any content that computer scientists find interesting. People from all walks of life welcome, including hackers, hobbyists, professionals, and academics.
- Sr/sciencememes ↗ 3,894,898 members · since 2012
Science Memes
What these communities upvoted this week
A cross-section of this week's top posts from the bigger science subreddits, in the order Reddit ranks them.
- Magic mushroom compound psilocybin grows new brain connections within 24 hours and repairs circuits damaged by chronic stress in mice. Scientists found the brain rewiring runs on …r/science · Oct 25
- Astronomer here! Big news- I am a winner this year for the Wendy and Eric Schmidt Awards for Excellence in Science Communications, in large part for my posts on Reddit!r/space · Oct 27
- With lab grown meat becoming more popular would it be possible to lab grow yourself and make steaks out of your lab grown self?r/askscience · Oct 27
- 31.4% of Young Women vs. 11.4% of Young Men Identify as LGBTQ+: What It Could Mean for Heterosexual Datingr/psychology · Oct 24
- Researchers found that older adults who napped frequently—defined as most days or every day—had a 48% higher risk of developing dementia compared to those who rarely or never napp…r/science · Oct 24
- Toronto, Canada photographed from the International Space Stationr/space · Oct 24
- Are there any examples of an invasive species that was soon wiped out because a predator (i clouding humans) found them to be delicious?r/askscience · Oct 26
- The menstrual cycle appears to modulate the severity of ADHD traits in women taking common stimulant medications. These traits peak in severity during menstruation and ease soon a…r/psychology · Oct 26
Choosing where to post
If you have a question, start in r/askscience: it is set up for exactly that, and with about 193 new posts a day there are plenty of people around to answer. Competition for attention differs a lot: r/space has 28M members but only about 26 new posts a day — roughly one new post for every 1.1M members — while r/askscience gets about 193 a day, one for every 136.8K. A strong, well-made post therefore has more room to be seen in r/space; r/askscience is better when you want quick replies. Jokes and memes have their own home in r/sciencememes; the serious communities tend to remove them, so keep the two apart. Rule sets vary: of the communities we have rules for, r/space lists 14, against 5 in r/compsci, so a post that is fine in one can be removed in another.
Big subreddits give a post the widest audience, but they also bury it quickly; the mid-sized communities on this list are usually friendlier for questions and first posts. 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
What is the biggest science subreddit?
r/science is the largest, with 34,575,992 members, followed by r/space (28M) and r/askscience (26.4M).
Which science subreddit is the most active?
By new posts per day, r/askscience leads with about 193, ahead of r/science (38). Counts are averages over the last seven days.
Where should a beginner ask about science on Reddit?
r/askscience is the one built around questions and advice, with about 193 new posts a day. Check its rules and search it first — common questions have usually been answered.
How many science subreddits are there?
We list 6 active, safe-for-work science communities with at least 25,000 members each, 101.8M 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 science subreddit?
r/science, created on Oct 18, 2006.
Are these science 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 (Oct 30, 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.