Find subreddits similar to any community
Two answers to “what else is like this?” — communities that discuss the same things, and communities whose posters are literally the same people. Free, no login.
Two kinds of “similar”
Ask most tools for subreddits like r/SaaS and you get a list of communities with SaaS-adjacent names. That is topic matching, and it is genuinely useful — it is what the Similar by content tab does, comparing an embedding of each community’s subject matter so that semantically close communities surface even when their names share nothing.
But topic similarity does not tell you where the people are. The Shared audience tab answers a different question entirely: of the accounts that posted here, how many also post over there? That surfaces the non-obvious neighbors — the hobby subreddit half your customers are in, the regional community, the adjacent profession — that no amount of topic matching would ever find. When the two tabs disagree, the audience tab is usually the more actionable one.
How to read the overlap numbers
The headline figure is the overlap coefficient: shared posters as a share of the smaller community’s posters. If it reads 14%, roughly one in seven of the people posting in the smaller of the two communities also posts in the other. It is the right measure when sizes are lopsided, because a 5,000-member community can never overlap much with a 3-million-member one by any proportional measure, even when every single one of its posters is also in the big one.
Underneath it we show Jaccard: shared posters divided by everyone who posted in either community. It is a stricter, symmetric measure, and it is the better read when the two communities are comparable in size. And we show the raw shared poster count, because a 40% overlap built on 12 accounts is noise and you deserve to see that for yourself.
One honest caveat: overlap is computed from posts we have crawled, not from all of Reddit. It measures observed posting behaviour, not lurkers, and it grows more reliable the longer a community has been in our catalog.
What to do with the list
The obvious use is expanding a shortlist beyond the one big subreddit in your niche — the saturated one where every founder in your category is already posting. The better use is triangulation: run the tool on your top three communities and look for the neighbors that appear in all three lists. Those are the communities your audience actually lives in, rather than the ones your category name suggests.
Before committing to any of them, open its stats page and check posting activity and promo tolerance — a high-overlap community with two posts a week is not worth a slot in your rotation. Then hit Watch and let Prowlo crawl it into your Dataset, where your agent can query it over MCP instead of you refreshing tabs.
Frequently asked questions
How do you decide which subreddits are similar?
Two independent ways, shown as separate tabs. "Similar by content" compares an embedding of each community's description and subject matter, so it finds subreddits that talk about the same things. "Shared audience" counts how many distinct people posted in both communities over the window we have crawled, so it finds subreddits with genuinely overlapping membership. They often disagree, and the disagreement is the useful part.
What is audience overlap and how is it calculated?
We take the set of accounts that posted in each subreddit and compare them. The headline percentage is the overlap coefficient — the share of the smaller community's posters who also post in the other one. The Jaccard figure underneath is stricter: shared posters as a share of everyone who posted in either community. Overlap coefficient is the better signal when the two communities are very different sizes; Jaccard is the better signal when they are comparable.
Why is the shared-audience list empty for my subreddit?
Overlap is computed from posts we have actually crawled, so a community we started tracking recently, or one that posts rarely, will not have enough observed authors to produce a reliable number yet. That is why we show nothing instead of guessing. The content tab works from day one.
Why would I want similar subreddits at all?
Because posting the same thing in one community five times gets you banned, and posting it once each across five genuinely related communities does not. It is also the fastest way to escape the obvious subreddit in your niche — the big one everyone already targets and where every thread is saturated — and find the smaller neighbors where your answer is still useful.
Is this free?
Yes, with no account. Signing in with a free Prowlo account raises the number of neighbors shown from 5 to 20 per tab.
What if a subreddit isn't tracked?
We only return communities in our active catalog, which excludes NSFW, private and unreachable subreddits. If yours is missing, search for it in the subreddit finder — adding it as a Watcher on a free account brings it into the crawl.