Platform character limits at a glance

X / Twitter: 280 characters (URLs count as 23).
Instagram caption: 2,200 characters.
LinkedIn post: 3,000 characters.
Facebook post: 63,206 characters.
TikTok caption: 2,200 characters.
Pinterest pin: 500 characters.
Threads: 500 characters.
Bluesky: 300 characters.
Mastodon: 500 characters (server default; may vary).

Twitter URL counting

X wraps all URLs through its t.co shortener, so every URL - regardless of length - counts as exactly 23 characters in the character limit. This tool applies that substitution automatically so your character count matches what X shows natively.

Optimal post length by platform

While longer posts are allowed, research consistently shows that shorter posts get higher engagement:

Platform	Optimal length	Source
X / Twitter	71–100 characters	Track Social research
LinkedIn	150–300 characters	LinkedIn internal data
Facebook	Under 80 characters	BuzzSumo analysis
Instagram	138–150 characters	Sprout Social
Threads	Under 150 characters	Early platform data

Emoji character counting

Emoji count as more than one character in some contexts:

JavaScript / most APIs: emoji outside the Basic Multilingual Plane (BMP) are encoded as UTF-16 surrogate pairs, counting as 2 code units. The laughing emoji 😂 is 2 code units in JavaScript's string.length.
ZWJ sequences: family emoji like 👨‍👩‍👧‍👦 are composed of multiple emoji joined by zero-width joiners (U+200D) and can be 8–11 code units. X counts the entire sequence as a single "weighted character."
X (Twitter) behavior: X uses its own weighted character counting that treats most emoji as 2 characters (not their raw UTF-16 length), which is reflected in this tool's X count.

Hashtags and mentions

On X, Instagram, and LinkedIn, hashtags and @mentions count toward the character limit exactly like any other text - each character including the # or @ symbol is counted. X is an exception for @mentions in replies: the @username of the person you're replying to does not count against the 280-character limit.