Subreddit overlap finder.
Two subreddits with shared members behave like one big audience. Post in one, the other often picks it up. The trick is knowing which overlaps actually contain buyers for your idea, not just warm bodies. Gorilla maps overlap and ranks the overlapping posts by intent.
What is subreddit overlap?
Subreddit overlap is the percentage of users who are active in two or more subreddits at the same time. If a third of r/SaaS posters also show up in r/microsaas, those two communities have a high overlap. The reason founders care: when overlap is real, posts that perform in one community tend to perform in the other. The audience is largely the same brain, browsing two doors.
Overlap matters because Reddit reach is fragmented. There is no single mega-sub that holds all of your potential users. They are scattered across five or ten communities that look unrelated by name but share a member base. Find that cluster and you have your distribution map. Miss it and you spend weeks posting into rooms that look right but have no shared audience with the people you need.
How to use a subreddit overlap tool
- Find audience-extending subs for cross-posting. If your post hit in r/SaaS, the overlap report tells you the next 3 subs where the same readers will see it. Cross-post there next, not into a random "big" sub.
- Spot adjacent niches. A 25% overlap with a sub you have never posted in is a tip. Go read it for an hour. The vocabulary, pain points and competitors people mention there are usually a few months ahead of your home sub.
- Avoid wasted effort on disjoint communities. Two subs with the same topic name can have near-zero shared users (different mods, different rules, different demographics). Overlap saves you from posting into the second one and watching it die.
- Map your competitor's footprint. Run overlap on the subs your competitor markets in. You get the full ring of communities they are working, plus the gaps you can own first.
- Pick beachhead + flank. Choose one home subreddit (where you are a real member) and 2-3 high-overlap flanking subs (where you cross-post and answer questions). That is the entire Reddit GTM for most pre-launch founders.
Why most subreddit overlap tools miss the mark
The other tools stop at the percentage. r/SaaS overlaps r/Entrepreneur by 28%, cool, what now? A 28% overlap of casual lurkers is worthless. A 12% overlap of people writing posts that start with "looking for a tool that…" is gold. The percentage hides the only number that actually matters for a founder: how many of those overlapping members are about to buy something.
Gorilla flips it. Instead of just listing overlap percentages, it scores the overlapping posts. You get back the subs that share an audience with your home sub and the actual buying-intent posts inside that overlap. Two subs can have a small overlap on paper and still be the highest-converting flank for your product, because the slice they share is exactly your buyer.
Founder-relevant subreddit overlap pairs
A few pairs we see come up in almost every founder run:
- r/SaaS ↔ r/microsaas. Heavy overlap. Same indie operator crowd, slightly different stage. If a launch lands in one, queue the second within 48 hours.
- r/Entrepreneur ↔ r/SideProject. Heavy overlap, but tone shifts. r/Entrepreneur leans business question, r/SideProject leans show-and-tell. Reframe the post, don't copy paste.
- r/buildinpublic ↔ r/indiehackers. Heavy overlap. The buildinpublic crowd lives on both. Same post, different framing on each.
- r/marketing ↔ r/SEO. Partial overlap. Founders mistake them as twins. They aren't. Overlap is real on technical SEO discussion and almost zero on positioning posts.
- r/startups ↔ r/YCombinator. Partial overlap with a status gap. Cross-posting works for hiring and fundraising threads, not for product launches.
Run Gorilla on your idea to find which overlapping subreddits have the highest buying intent.
Run Gorilla ($0.99)