How the comparison works
Type two subreddit names, with or without r/ in front, and press Compare. Each count is the exact member number Reddit keeps for the community, the one it stopped showing on subreddit pages in 2025. The gap updates with every new reading.
Why the gap moves in small steps
Reddit refreshes member counts about once a minute and two reads a few seconds apart can differ by one or two. A drop of 5 or less only shows once it has lasted a minute, so the gap does not flicker.
For one subreddit with its daily history, open it on the subreddit member count page.