Mastodon Post Preview & Thread Splitter
See your post in a Mastodon-style preview, counted the way Mastodon counts it, against 500 or your server's own limit. Switch to thread mode to split a long post into posts that each fit.
Links count as 23 · A remote mention counts as @user · Every emoji counts as 1
Live preview
Your Name
@yourname@mastodon.social
Your post content will appear here...
Splitter prefers paragraph breaks → sentence ends → word boundaries · Links never split
Your Name
@yourname@mastodon.social
Your post content will appear here...
How it works
Simple and instant
Type or Paste Your Post
Enter your post and watch the preview update as you type. Links count as 23, a mention of someone on another server counts as its @user part, and every emoji counts as 1.
Set Your Server's Limit
Mastodon's default is 500 characters. If your server allows more, enter its limit in Server limit, in either mode, and the count and the splitter follow it.
Split, Then Copy Each Post
Thread splitter breaks long text into posts that fit your limit, with optional numbering (none, 1/N or 🧵), and never cuts inside a link. Copy each post, or Copy all for the whole thread.
FAQ
Frequently asked questions
How Long Can a Mastodon Post Be?
500 characters on a default Mastodon server, and each server can set its own limit. Every link that starts with http:// or https:// counts as 23, a mention of someone on another server counts only its @user part, and every emoji counts as 1. For the count on its own, use the Mastodon Character Counter.
Why Does a Link Look Shorter in the Preview?
Mastodon shows a link without its https:// and www., cut after 30 characters with an ellipsis, and the preview does the same. The full address is still the link, and it still counts as 23 characters.
How Do I Find My Server's Character Limit?
Open https://your.server/api/v2/instance in your browser, with your server's address in place of your.server, and look for max_characters under configuration and statuses. The page is public, so you don't need to sign in.
How Does the Thread Splitter Decide Where to Split?
It works down a priority list. It first tries a paragraph break (a blank line), then the end of a sentence (a full stop, exclamation mark or question mark followed by a space), then a word boundary. If a run of text has no spaces at all, it cuts between characters. Links are never split.
Does the Preview Show Images or Video?
No. The preview shows the text of your post. A Mastodon post can also carry up to 4 images or one video, which this tool leaves out.
Is This Tool Free?
Yes. No account, no sign-up and no credit card. The preview and the splitter run entirely in your browser.
Sources, checked on October 27, 2026: Mastodon docs: Posting to your profile, Mastodon docs: instance API methods and Mastodon source: TextFormatter.
Schedule Your Mastodon Threads in Postopus
Postopus publishes to Mastodon and Bluesky as well as LinkedIn and X, with threads, up to 4 images with alt text, a first comment posted as a reply, and scheduling. Each Mastodon post is checked against your server's own limit, 500 by default.
7-day trial · No credit card required