# What is a subreddit?

Canonical: https://postmesh.app/glossary/subreddit

By PostMesh team. Published 2026-10-31; updated 2026-10-31.

A subreddit is a community on Reddit devoted to one topic, with a name that starts with r/, its own rules and its own volunteer moderators. Reddit now mostly calls them communities, and the two words mean the same thing.

## What a subreddit means

[Reddit](/platform/reddit) is one big site made of many smaller communities, and each of those smaller communities is a subreddit. Reddit's help center describes them as sub-communities within Reddit that are created and moderated by users. Its list of common expressions puts it even more simply: subreddit is another name for a community.

Every subreddit has a topic and a name. The name appears at the top of the community and forms its web address, reddit.com/r/ followed by the name, which is why people write subreddits as r/gardening or r/AskScience. When someone says "post it on the cooking sub" or "that's a question for r/legaladvice", they're pointing you to the right room in a very large building.

What makes subreddits feel so different from each other is that the people running them make their own choices. Reddit says each community has its own focus, look and rules, including what's on-topic and how members are expected to behave. A joke that gets thousands of upvotes in one subreddit can get you banned from the next one over.

## Where the word subreddit comes from

The word is Reddit plus the prefix sub-, meaning under. [Dictionary.com](https://www.dictionary.com/e/slang/subreddit/) explains it that way, as communities that sit under the broader Reddit umbrella, and notes that the site's own name is a play on the phrase "I read it".

According to Dictionary.com, Reddit launched in 2005, the first two subreddits were r/reddit and r/NSFW, and ordinary users were allowed to create their own subreddits beginning in 2008. Its entry, written in November 2018, counted more than 850,000 subreddits as of June 2018. Reddit's help center today describes the site as having over 100,000 communities. The two figures come from different years and may not count the same way, so treat neither as a live total.

- 2005: Reddit launches, per Dictionary.com
- Early days: The first two subreddits are r/reddit and r/NSFW
- 2008: Users can create their own subreddits
- June 2018: More than 850,000 subreddits, per Dictionary.com
- Today: Reddit's help center describes over 100,000 communities

*Sources: Dictionary.com's subreddit entry and Reddit Help: What is Reddit?*

## How subreddits work

Two layers of rules apply in every subreddit. The Reddit Rules cover the whole site, and each community adds its own on top, which its moderators define and enforce. Reddit's help center notes that some communities have very specific rules about how to format a post or how strictly to stay on topic. Those rules live in the community sidebar on the web, or under the About tab in the app.

Moderators, or mods, are users who volunteer to run a community. Reddit says they can style it, create user and post [flair](/glossary/reddit-flair), organize [AMAs](/glossary/ama), remove posts that don't fit, ban rule-breakers from that community and add other mods. They can't ban anyone from Reddit as a whole, which only Reddit's paid admins can do, and they can't delete a post from the site, only remove it from their community.

Not every subreddit is open to everyone. Reddit has four community types, and the type decides who can read and who can take part.

| Type | Who can view | Who can post and comment |
| --- | --- | --- |
| Public | Anyone | Anyone with a Reddit account |
| Restricted | Anyone, and anyone can vote | Only approved members, depending on the settings |
| Private | Only members approved by the mods | Only members approved by the mods |
| Premium-only | Only Reddit Premium members | Only Reddit Premium members, and only on old.reddit.com |

Reddit has also changed how it describes a community's size. Instead of total members and people online, communities now show weekly visitors, the unique users who visited in the past seven days based on a 28-day rolling average, and weekly contributions, the posts and comments made in the past seven days. Reddit says the old member count reflected a community's age more than its activity, since it included people who joined years ago and never came back.

## How to find and join a subreddit

Joining puts a community's posts in your home feed. You can join as many as you like, though Reddit says any single visit to your home feed only draws from around 250 communities and refreshes every 30 minutes.

1. **Search for your topic**: Use the search bar on reddit.com or the search icon in the app. You don't need to type r/ before the name.
2. **Open the Communities results**: On the web, look for the Communities section of the results. In the app, tap the Communities tab.
3. **Look around first**: Open the community, read the sidebar or About tab, and scroll a few posts to see if it's what you wanted.
4. **Tap Join**: The community is added to your home feed and your list of joined communities.
5. **Leave any time**: Open the community and click or tap Joined. In the app, a menu pops up with a leave option.

If you don't know what to search for, Reddit suggests the Explore Communities option in the left-hand menu, which recommends communities by topic and trend, plus r/findareddit, r/newreddits and r/popular. If you follow several subreddits on one subject, a custom feed lets you group them, such as three film communities under one feed called Movies, and you can keep it private or share it.

Reddit app: Menu icon, top left › Explore Communities › Pick a topic › Join

*From Reddit Help: How do I browse and find communities on the Reddit app?*

## How to post in a subreddit without getting removed

Most removed posts break a community rule the poster never read. Reddit's own advice for getting noticed starts with choosing the most relevant community and following its formatting rules, and its Reddiquette asks you to read a community's rules, usually found in the sidebar, before you submit. A few habits help.

- Read the rules in the sidebar or About tab, including any pinned posts from the mods.
- Check whether the community requires a flair on every post and which one fits yours.
- Check which post types are allowed. Some communities only take text posts, others only links or images.
- Search the community for your question first. Reddiquette asks people to look for duplicates before posting.
- Write a clear, factual title. Reddit notes that titles can't be edited after you submit.
- Expect filters on new accounts. Reddit says some communities require a certain amount of karma before you can post, to keep out spam.

That last point catches a lot of people. Our guide to [Reddit karma requirements](/blog/reddit-karma-requirements) explains how those thresholds work and how to build up the karma some communities ask for. Once a post is up, [upvotes](/glossary/upvote) from members push it up the community's feed, and you become the [OP](/glossary/op) that commenters will address. If you want help drafting the post itself, the [Reddit post generator](/tools/reddit-post-generator) can get you started.

## How to create your own subreddit

Anyone can start a community. On reddit.com, Reddit says you click Create Community in the left-hand sidebar. In the app, you open the left community drawer and tap Start a Community. Either way, you give it a name and a description, add up to three topics so Reddit can connect it with the right people, pick a community type, and decide whether to mark it Mature (18+).

Choose the name carefully. It must be 3 to 21 characters, and once the community exists you can't change it, not even the capitalization. Reddit also says communities can't be deleted once created. A banner and avatar are optional at the start, and if you're making one, the [Reddit banner resizer](/tools/reddit-banner-resizer) crops an image to the right size.

**Before you start a subreddit**
- [ ] You know what the community is for and who it serves
- [ ] You searched for an active community with the same purpose
- [ ] If a similar community is unmoderated, you considered r/redditrequest
- [ ] You're willing to moderate it, or have help lined up
- [ ] You checked the name's spelling and capitalization, since it can't change
- [ ] You've read the Reddit Rules and the Moderator Code of Conduct

*Based on Reddit Help: Things to know before creating a community.*

Reddit's advice is to think twice if a thriving community on the same topic already exists. Joining it, taking part and later volunteering to moderate can have more impact than starting from zero. If you do go ahead, make your community distinct from the ones already there.

## Subreddit compared with similar Reddit terms

| Term | What it means |
| --- | --- |
| Subreddit | A Reddit community about one topic, written as r/ plus its name |
| Community | Reddit's current word for a subreddit |
| Sub | Casual short form, as in "the gardening sub" |
| Custom feed | Your own grouping of several communities, once called a multireddit |
| Mod | A volunteer who helps run a subreddit |
| Admin | A Reddit employee who handles sitewide issues |

If a subreddit itself is breaking the Reddit Rules, you can report it to Reddit rather than to its moderators. Reddit's help center asks you to submit a report while logged in, and our guide on [how to report a subreddit](/blog/how-to-report-a-subreddit) walks through each kind of report. For anything that's only against a community's own rules, message that community's mods from the sidebar instead.

## Questions

### Is a subreddit the same as a Reddit community?

Yes. Reddit's help center says subreddit is another name for a community, and Reddit's own menus now mostly use the word community.

### What does r/ mean on Reddit?

It marks a subreddit. A community's web address is reddit.com/r/ followed by its name, so r/books means the books community.

### Who runs a subreddit?

Volunteer moderators who are regular Reddit users. They set and enforce the community's rules, while Reddit's paid admins handle the sitewide rules.

### Can you rename or delete a subreddit?

No. Reddit says a community's name can't be changed after it's created, including capitalization, and communities can't be deleted once created.

### How long can a subreddit name be?

Between 3 and 21 characters, according to Reddit's help center.

### Why can't I post in a subreddit I joined?

It may be restricted to approved members, require flair, allow only certain post types, or filter new accounts. Check the rules in its sidebar or About tab.

## Related terms

- [Upvote](https://postmesh.app/glossary/upvote)

- [Flair](https://postmesh.app/glossary/reddit-flair)

- [OP](https://postmesh.app/glossary/op)

- [AMA](https://postmesh.app/glossary/ama)

- [Hashtag](https://postmesh.app/glossary/hashtag)

## Sources

- [Reddit Help: What are communities or "subreddits"?](https://support.reddithelp.com/hc/en-us/articles/204533569-What-are-communities-or-subreddits)

- [Reddit Help: What do these expressions mean?](https://support.reddithelp.com/hc/en-us/articles/205313845-What-do-these-expressions-mean)

- [Reddit Help: What is Reddit?](https://support.reddithelp.com/hc/en-us/articles/204511479-What-is-Reddit)

- [Reddit Help: What are public, restricted, private, and premium-only communities?](https://support.reddithelp.com/hc/en-us/articles/360060416112-What-are-public-restricted-private-and-premium-only-communities)

- [Reddit Help: What's a moderator?](https://support.reddithelp.com/hc/en-us/articles/204533859-What-s-a-moderator)

- [Reddit Help: What are Reddit's rules?](https://support.reddithelp.com/hc/en-us/articles/360043503951-What-are-Reddit-s-rules)

- [Reddit Help: What is the community sidebar?](https://support.reddithelp.com/hc/en-us/articles/28621482218260-What-is-the-community-sidebar)

- [Reddit Help: Understanding weekly visitors and contributions on Reddit](https://support.reddithelp.com/hc/en-us/articles/41043361207316-Understanding-weekly-visitors-and-contributions-on-Reddit)

- [Reddit Help: How to join or leave a community](https://support.reddithelp.com/hc/en-us/articles/28621027395220-How-to-join-or-leave-a-community)

- [Reddit Help: How do I browse and find communities on the Reddit app?](https://support.reddithelp.com/hc/en-us/articles/17881389378196-How-do-I-browse-and-find-communities-on-the-Reddit-app)

- [Reddit Help: What is a custom feed and how do I make one?](https://support.reddithelp.com/hc/en-us/articles/360043043412-What-is-a-custom-feed-and-how-do-I-make-one)

- [Reddit Help: What can I do to get my posts noticed?](https://support.reddithelp.com/hc/en-us/articles/204519249-What-can-I-do-to-get-my-posts-noticed)

- [Reddit Help: Reddiquette](https://support.reddithelp.com/hc/en-us/articles/205926439-Reddiquette)

- [Reddit Help: What is karma?](https://support.reddithelp.com/hc/en-us/articles/204511829-What-is-karma)

- [Reddit Help: How to create a community](https://support.reddithelp.com/hc/en-us/articles/15484258409492-How-to-create-a-community)

- [Reddit Help: Things to know before creating a community](https://support.reddithelp.com/hc/en-us/articles/15484184612116-Things-to-know-before-creating-a-community)

- [Dictionary.com: subreddit (Wayback Machine copy, December 2025)](https://web.archive.org/web/20251207140223/https://www.dictionary.com/e/slang/subreddit/)