Social media post limits: captions, image ratios and video length
Every network has its own rules for what it will publish, and the post that breaks one usually does so at the worst moment: after approval, at publish time. This table collects the limits that matter when planning a post, and the sections after it explain which ones actually bite.
These are the same rules our editor checks as you write, so the table is kept in step with the product.
At a glance
| Limit | X (Twitter) | TikTok | YouTube | |||
|---|---|---|---|---|---|---|
| Caption limit | 2,200 chars | 63,206 chars | 280 chars | 3,000 chars | 2,200 chars | 5,000 chars |
| Visible before “more” | ~125 chars | ~480 chars | Full post | ~210 chars | ~100 chars | ~157 chars |
| Image aspect ratio | 4:5 – 1.91:1 (refused outside) | Any (fitted) | 1:3 – 3:1 (cropped outside) | Any (fitted) | Video only | Video only |
| Minimum image width | 320 px | 320 px | 240 px | 320 px | — | — |
| Video length | 3 s – 1 min 30 s | 1 s – 4 h | 0.5 s – 2 min 20 s | 3 s – 10 min | 3 s – 10 min | 1 s – 12 h |
| Most media per post | 10 | 10 | 4 | 9 | 1 | 1 |
| Text-only posts | No — media required | Yes | Yes | Yes | No — video required | No — video required |
| Hashtag limit | 30 | — | — | — | — | — |
| Links clickable in caption | No | Yes | Yes | Yes | No | Yes |
One network at a time:InstagramFacebookX (Twitter)LinkedInTikTokYouTube
How to read these limits
The numbers here are the limits for publishing through a scheduling tool — each network’s publishing API — which is how most agencies and teams post. Posting by hand in a network’s own app can allow a little more on some limits, and networks change their rules from time to time, so treat the table as the line to plan inside rather than a target to hit.
Two kinds of limit matter. Hard limits decide whether a post publishes at all: caption length, a missing video, an image shape a network refuses. Soft limits decide how the post looks once it is live: where the caption is cut off, how an image is cropped, which carousel slides are shown.
Rejected versus cropped
Not every limit is a hard stop. Instagram refuses an image outside its 4:5 to 1.91:1 range outright. X accepts almost any shape and crops it in the timeline instead. Facebook fits whatever it is given. Knowing which is which decides whether you need a new crop or just a heads-up to the client.
| Network | Image outside the range | What to do |
|---|---|---|
| Refused | Re-crop to between 4:5 and 1.91:1 before sending | |
| X | Accepted, cropped in the timeline | Check the crop keeps the subject in frame |
| Facebook, LinkedIn | Fitted | Any shape publishes; portrait and square use the most space |
| TikTok, YouTube | Video only through publishing | Plan the video first |
The caption limit is not the one that matters
Instagram allows 2,200 characters, but shows about 125 before “more”. LinkedIn cuts around 210. TikTok shows roughly 100 over the video. The practical limit for a hook is the truncation point, not the maximum — the rest of the caption is only read by people the first line already convinced.
- Put the point of the post in the first sentence
- Move hashtags and credits to the end, or to a first comment
- Check each network’s preview rather than counting characters by eye
X is the exception: at 280 characters there is no “more” — the whole post is the hook.
Links: counted, clickable, or neither
On X, every link counts as 23 characters however long it really is, because it is wrapped in a short link. A long tracking URL costs the same as a short one; a short one still costs 23.
Instagram and TikTok don’t make links in captions clickable. A URL there takes up space without taking anyone anywhere — point people to the link in the profile instead. Facebook, LinkedIn and YouTube descriptions do make links clickable.
Hashtags and mentions
Instagram caps a post at 30 hashtags and 20 mentions; go over and the post is refused rather than trimmed. Other networks don’t publish a hard cap, but every hashtag still takes characters from the caption. A handful of specific hashtags does more than a long generic list on every network.
Image sizes that work everywhere
Most teams export images at 1080 pixels wide. Three shapes cover almost every post:
| Shape | Size at 1080 wide | Best for |
|---|---|---|
| 4:5 portrait | 1080 × 1350 | Instagram and Facebook feeds; the most screen space |
| 1:1 square | 1080 × 1080 | The safe choice when one image goes to several networks |
| 1.91:1 landscape | 1080 × 566 | Link-style images; the widest Instagram accepts |
If a single image is going to Instagram and X together, 4:5 is accepted on both — but X crops tall images in the timeline, so keep the subject away from the top and bottom edges.
Video length and shape
Video limits vary more than anything else in the table: from a couple of minutes on X to many hours on YouTube and Facebook. The minimums catch people out too — a one-second clip is too short for several networks.
- Shoot vertical (9:16, 1080 × 1920) for TikTok, Reels and Shorts
- Keep one edit under the shortest limit of the networks it is going to
- Choose the cover frame deliberately; an automatic first frame is often a blur
Where text-only posts work
Facebook, X and LinkedIn publish words on their own. Instagram and TikTok need media, and YouTube needs a video. Plan the creative before the caption for those three — and before the month’s calendar is sent for review.
Carousel counts
Instagram and Facebook take up to 10 items in a carousel, LinkedIn 9 and X 4. Extras beyond the limit are dropped rather than refused — so the last slides of an over-long carousel silently never appear, and a story told in ten slides loses its ending on X.
Every slide is held to the same shape rules as a single image. A carousel whose fourth slide is too tall for Instagram fails just as if it were the first.
Planning one post for several networks
- 01Start from the strictest network the post is going to — usually Instagram for images, the shortest video limit for video
- 02Crop to a shape every target network accepts, or make one crop per network
- 03Count carousel slides against the smallest limit, or accept that later slides drop
- 04Write the hook inside the shortest truncation point
- 05Split the caption per network where one needs a link and another can’t use it
- 06Check every preview before sending it for approval
Or let the editor do the counting: every post is checked against these rules while it is written, and anything a network would refuse blocks sending before the client ever sees it.