Learn
Every character limit here is cross-checked against the platform’s own developer documentation. X’s counting rules for URLs and emoji are documented in their character-counting reference. X Developer: counting characters.
Learn
Character Limit Cheat Sheet
Every platform character limit on one page. Verified against each platform’s own documentation.
Social
- Twitter / X post: 280
- Instagram bio: 150
- Instagram caption: 2,200
- Facebook post: 63,206 (See more at 477 desktop, 250 mobile)
- LinkedIn post: 3,000 (See more at 210)
- LinkedIn headline: 220
- Threads: 500
- Bluesky: 300
- Mastodon: 500 (instance override)
- TikTok caption: 4,000
- Reddit title: 300
- Pinterest description: 500
Publishing
- YouTube title: 100 (search truncates around 70)
- YouTube description: 5,000 (Show more at 157)
Ads
- Google Ads RSA headline: 30 (up to 15 slots)
- Google Ads RSA description: 90 (up to 4 slots)
SEO
- Meta title: 60 characters or 580 pixels
- Meta description: 155 to 160 desktop, 120 mobile
SMS
- SMS GSM-7: 160 per segment
- SMS Unicode: 70 per segment
Common questions
Why do some platforms count graphemes and others count code units?
Modern platforms (Bluesky, Threads) count graphemes because that is what users see. Legacy platforms (Twitter, most SMS gateways) count UTF-16 code units for backward compatibility.
Does the URL rule vary by platform?
Yes. Twitter and Mastodon shorten every URL to a fixed length (23 chars). LinkedIn and Instagram do not shorten; the URL counts as its literal length.
What about emoji?
Most platforms count emoji as 2 to 4 characters. Compound emoji (family, profession, flag) count as their code-unit total, often 8 to 11.
How often do the limits change?
Once or twice a year on the fast-moving platforms. Every change here is dated and cross-referenced against the platform's developer docs.
Is a "safe" length always the limit minus 10?
Yes for text-only posts. For posts with emoji or URLs, budget by the encoded length, not the raw character count.