Mastodon Character Limit: 500, and How to Find Your Server's

Mastodon's character limit is 500 on a standard server, but each server can run its own, so your limit depends on where your account lives. On October 19, 2026, mastodon.social allowed 500 and infosec.exchange allowed 11,000, and you can check your own server in about ten seconds.

How to check your server's limit

Every Mastodon server publishes its settings at the same address. To read yours:

1. Open https://your.server/api/v2/instance in a browser, with your server's name in place of your.server. For mastodon.social, that's https://mastodon.social/api/v2/instance.
2. Find "statuses" inside "configuration".
3. Read max_characters. That's your limit. characters_reserved_per_url next to it is what one link costs.

Your browser shows the page as raw data. Most browsers have a "Pretty print" box or a JSON view that makes it easier to scan, or you can search the page for max_characters.

Mastodon's own app counts down from this number as you type. A post that arrives over the limit through the API, from a scheduler or a bot, is rejected with an error that names the limit.

Limits on some well-known servers

We read these from each server's instance API on October 19, 2026. Admins can change them, so check again before you rely on one.

Why servers have different limits

In standard Mastodon, 500 is written into the code as a fixed number, and there's no admin setting to change it. A server with a higher limit is running modified software.

Two of the servers above, tech.lgbt and infosec.exchange, run glitch-soc, a Mastodon fork that reads the limit from a setting called MAX_TOOT_CHARS and falls back to 500 when it isn't set. mathstodon.xyz reports a standard version number and still allows 1,729, so its admins have changed their copy of the code another way. Either way, the number is the admin's choice, and it can change.

What counts toward the limit

Mastodon counts graphemes, which are characters as you see them, so an emoji counts as 1. Before counting, it rewrites links and mentions:

Two of these trip people up. The content warning isn't free: Mastodon joins it to the post text and counts both, so a long warning shrinks the post. And a link only gets the 23 rate when it starts with http:// or https://, so paste full addresses. Our guide to content warnings on Mastodon covers when to use one and how to keep it short.

A worked example

Here's a post with a content warning, a remote mention, a long link and a hashtag:

Content warning: Spoilers: Andor season 2

Thanks @alice@mastodon.social for the recap. My notes on the finale, scene by scene: https://example.com/blog/andor-season-2-finale-notes #Andor

Typed out, the post text is 144 characters. Mastodon counts it like this:

• The 52-character link costs 23, which saves 29.
• @alice@mastodon.social costs 6, which saves 16.
• That leaves 99 for the post text.
• The 24-character warning is added: 99 + 24 = 123.

So the post uses 123 of a standard server's 500.

The other limits on a post

The same instance address lists every other limit your server sets. Here's what mastodon.social reported on October 19, 2026:

Image descriptions get their own 10,000, separate from the post, so there's no reason to skimp on alt text to save room.

Long posts from other servers still arrive in full

Mastodon only checks the limit on posts written on its own server. A 3,000-character post from infosec.exchange shows up on mastodon.social in full, and you can reply to it from your 500-character account. The limit decides what you can write, not what you can read.

This matters when you follow people on high-limit servers and quote or reply to them: your reply still has your server's limit.

How to get a higher limit

Your options, from easiest:

1. Write a thread. Reply to your own post to continue. fedi.tips calls it polite to post the first part as Public and the replies as Unlisted, so only the start of the thread shows on live feeds and in search. Your followers still see every part. Our guide to writing a thread covers where to split.
2. Move to a server with a higher limit. Mastodon's move tool switches your followers to your new account, and you can export the accounts you follow, block and mute, then import them on the new server. Your posts don't move: Mastodon's docs say it can't import posts.
3. Ask your admin. If your server runs glitch-soc, the limit is one setting. If it runs standard Mastodon, raising it means changing the code and keeping that change through every upgrade.

Checking a post before it goes out

A counter that doesn't know Mastodon's rules can be wrong in either direction. One that counts every link in full stops you short on posts that would fit. One that ignores the content warning passes posts your server will reject.

The free Mastodon character counter asks your server for its limit and counts the way Mastodon does, content warning included. The lookup sends only the server's name, straight to that server.

In Shaflex, Mastodon gets its own copy of every draft, on any server, counted against 500 characters whichever server you post from, with the content warning set in the draft and sent with the post. Split automatically turns a draft that's too long into a thread, cut where sentences end. Here's how to schedule Mastodon posts step by step, and how the other four networks count in our character counting guide.

Sources

Checked on October 19, 2026.

• Mastodon docs: Posting toots (500 by default, links 23, mentions)
• Mastodon source: StatusLengthValidator (graphemes, content warning counted, local posts only)
• Mastodon API: GET /api/v2/instance
• Instance APIs read on October 19, 2026: mastodon.social, fosstodon.org, mstdn.social, tech.lgbt, mathstodon.xyz, infosec.exchange
• glitch-soc source: StatusLengthValidator with MAX_TOOT_CHARS
• Mastodon docs: Moving or leaving accounts
• fedi.tips: How do I post a thread on Mastodon?