Character limits, and the ones that truncate without telling you
Hitting the cap is the visible failure. The expensive one is the cutoff that happens hundreds of characters earlier, in the feed.
Two numbers, and the second one matters more
Every platform has a hard cap — the point where it stops accepting characters. Most also have a soft cutoff: the point where the feed stops showing your text and replaces the rest with “more”. The hard cap is announced. The soft cutoff is not, and it is usually an order of magnitude smaller.
| Field | Hard cap | Visible before “more” |
|---|---|---|
| Instagram caption | 2,200 | ~125 |
| YouTube description | 5,000 | ~150 |
| LinkedIn post | 3,000 | ~210 |
| Facebook post | 63,206 | ~477 |
| TikTok caption | 2,200 | Little, and it overlays the video |
| X post | 280 | All of it |
An Instagram caption has room for 2,200 characters and shows 125. Write the first sentence as though it is the only one, because for most of the people scrolling past, it is.
The rest of the table
| Field | Limit | Note |
|---|---|---|
| YouTube title | 100 | Cut off in search well before this |
| YouTube tags, all combined | 500 | Commas count |
| YouTube comment | 10,000 | |
| YouTube channel description | 1,000 | |
| Instagram bio | 150 | |
| Instagram alt text | 100 | |
| TikTok bio | 80 | The tightest field on any major platform |
| X bio | 160 | |
| LinkedIn headline | 220 | Follows you into every comment |
| LinkedIn about | 2,600 | |
| Pinterest pin title | 100 | |
| Pinterest description | 500 | |
| Twitch stream title | 140 | |
| Discord message | 2,000 | 4,000 with Nitro |
| Reddit title | 300 | |
| Threads post | 500 | |
| Meta description (SEO) | ~160 | Google rewrites most of them anyway |
| Page title (SEO) | ~60 | Truncated in results past about here |
Each of these has a live counter on the site that shows the count against the cap as you type, and turns over when you pass it.
The traps in counting
Hashtags count
On Instagram and TikTok, hashtags come out of the same caption budget as the prose. Thirty hashtags at an average of twelve characters is 360 characters of your 2,200 — and, more importantly, they sit between your first line and everything after it. The usual fix is to put them in the first comment instead; there is a tool for building that.
Links are counted oddly
On X, every link counts as 23 characters no matter how long it is, because the platform rewrites it internally. A 200-character URL costs you 23. Shortening a link before posting to X saves nothing at all.
An emoji is not one character
Most platforms count in UTF-16 code units, which means many emoji cost two, and emoji built from sequences — skin tones, flags, families — cost considerably more. A family emoji can be seven or more units. If a caption is right on the limit and full of emoji, expect the platform's count to disagree with the one in your text editor.
A truncated description loses your links
This is the one that actually costs money. YouTube descriptions routinely end with affiliate links, sponsor codes and social handles. All of it sits after the “more” fold, and a description that gets truncated is one where nobody sees any of it. Put anything that must be seen in the first 150 characters.
A working order
- Write the first line to stand alone. Instagram shows 125 characters; YouTube shows 150. That is your headline whether you meant it to be or not.
- Put anything load-bearing — a link, a code, a call to action — before the fold.
- Check the count against the real cap with a counter, not by eye.
- Move hashtags to a first comment if the platform allows it.
- Assume every number here will change, and re-check the ones that matter.