Mastodon character counter
Count characters for Mastodon posts. Configurable per-instance limits (default 500).
about the mastodon character counter
Mastodon gives you more room than X — the default limit is 500 characters per post — but because Mastodon is a network of independently run servers, the limit isn't universal. Each instance sets its own: mastodon.social uses the standard 500, while other servers allow 1,000, 5,000, or more. This counter tracks your character count in real time and lets you set the limit to match your instance.
Mastodon also counts differently than X. All links count as 23 characters regardless of their actual length, and when you mention someone on another server (@user@example.social), only the @user part counts — the domain is free. Those rules mean a raw character tally often overstates your real count, and this tool applies them so the number you see matches what Mastodon enforces.
Type or paste your post, pick your instance's limit (or keep the 500 default), and watch the count update as you write. When it fits, schedule it with PostAI to publish alongside your posts on X, LinkedIn, and the rest of your channels from one place.
frequently asked questions
What is the Mastodon character limit?
The default limit is 500 characters per post, but each Mastodon instance can set its own. mastodon.social uses 500, while some servers allow 1,000, 5,000, or even unlimited characters. Check your instance's about page or the composer counter to confirm yours.
Do links count toward Mastodon's character limit?
Yes, but every link counts as exactly 23 characters no matter how long the URL actually is. That means a 100-character URL only uses 23 of your 500 characters.
Do mentions count toward the Mastodon character limit?
Partially. For remote mentions like @user@example.social, only the @user portion counts toward your limit — the server domain is excluded. Local mentions count in full as typed.
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