Standard Mastodon allows 500 characters per post — but Mastodon is federated, and individual instances can raise that limit, so your real ceiling depends on where your account lives. Count against the 500-character default below; if your instance allows more, you have headroom.
0 / 500 characters · 0 words
500 characters left
The vanilla-Mastodon default (incl. mastodon.social). Your instance may allow more — check its about page.
Mastodon counts every link as 23 characters regardless of length, and only the username part of mentions counts (the @instance.domain part is free).
| Field | Limit |
|---|---|
| Post (default) | 500 charactersThe stock Mastodon limit; instance admins can modify it, and some instances allow thousands. |
| Any URL | counts as 23 charactersLinks are counted at a fixed 23 characters no matter their real length. |
| Mentions | only the @username part countsThe instance domain in a mention is excluded from the count. |
| Content warning text | counts toward the limit |
| Bio | 500 characters (default) |
| Display name | 30 characters |
Guide
Vanilla Mastodon — including the flagship mastodon.social — caps posts at 500 characters. But Mastodon is open source and federated: instance administrators can change the limit in their server’s code, and plenty have, with communities running anywhere from 1,000 to over 11,000 characters. Your effective limit is whatever your home instance configured, and posts from long-limit instances display in full when federated to short-limit ones.
The 500-character default remains the safe number to write against, especially if you schedule posts through tools that validate against standard Mastodon. This counter uses it as the baseline.
Mastodon counts more generously than most platforms. Every link costs a flat 23 characters no matter how long the URL — same trick as X, but on a bigger budget. Mentions are cheaper still: only the @username portion counts, while the @instance.domain suffix is free, which matters because full Mastodon addresses are long.
Content warnings deserve attention: the CW text counts toward your limit, so a long warning plus a long post can overflow in a way the draft alone would not. Hashtags count normally and matter more here than almost anywhere — Mastodon has no algorithmic feed, so tags are the main discovery mechanism.
With 500 characters and no algorithm deciding reach, Mastodon rewards substance and clear tagging over hook engineering. A good pattern: the post in plain language, then two or three specific hashtags at the end, since tag-following users are a large share of your potential audience.
If Mastodon is part of a broader posting routine, its limit pairs naturally with Threads (also 500) while X (280) and Bluesky (300) force shorter cuts. SocialKit publishes to Mastodon alongside the other ten networks and shows each one’s count while you compose — so the 500-character version and the 280-character version are siblings, not accidents.
500 characters per post by default (including on mastodon.social). Because instances can modify their own configuration, some communities allow much longer posts — check your instance’s about page for its limit.
Links count as a flat 23 characters regardless of length. For mentions, only the @username part counts — the instance domain is free. Content-warning text does count toward the limit.
Their home instance raised the limit. Mastodon is open source, and admins can configure longer posts; federated posts display in full even on instances with shorter limits.
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SocialKit shows every network’s character limit while you write, so one draft fits all 11 platforms — scheduled from a single calendar.
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