# How Long Can a Caption Be on TikTok, Instagram Reels, YouTube Shorts and Threads? URL: https://fulinlabs.com/blog/short-video-caption-length-limits-2026/ Published: 2026-11-11 Product: schedulepost Summary: Documented caption limits for TikTok, Instagram Reels, YouTube Shorts and Threads as of November 2026, what each one counts, and which claims are still unconfirmed. **For video posts published through each platform's API, the limits are 2,200 characters on TikTok and Instagram, 5,000 bytes for a YouTube description (plus a 100-character title), and 500 characters on Threads.** Checked against each platform's developer documentation on November 11, 2026. If you write one caption for several platforms, write to the shortest limit that applies, and check how each platform counts. I build [SchedulePost](https://schedulepost.fulinlabs.com), which posts one video to several networks, so cross-posting a single caption is the problem I deal with. The table below lists only figures I could confirm in the platform's own documentation. ## What are the caption limits for short-form video? | Platform | Caption limit | How it is counted | Source | | --- | --- | --- | --- | | TikTok | 2,200 | UTF-16 code units | TikTok Content Posting API, direct post reference | | Instagram (feed and Reels) | 2,200 characters, 30 hashtags, 20 @ tags | characters | Instagram Graph API, IG User media reference | | YouTube Shorts | 5,000 description, 100 title | bytes (description), characters (title) | YouTube Data API, videos resource | | Threads | 500 | characters; emoji counted as UTF-8 bytes | Threads API, posts | The Instagram reference gives one caption limit for all media containers and no separate Reels number. Facebook and X also have limits that the [caption character checker](https://schedulepost.fulinlabs.com/tools/caption-length) compares; they are not in the table because I did not verify them in this check. ## Does TikTok really allow 4,000 characters? Possibly in the app, not through the API. Several third-party guides say TikTok's app accepts captions of about 4,000 characters, but I found no statement of that in TikTok's own documentation. The documented limit for a video caption sent through the Content Posting API is 2,200 UTF-16 code units. Because schedulers publish through that API, a caption that works when typed in the app can still be refused when scheduled. Keep scheduled captions at 2,200 or below. ## Did Instagram cut hashtags to 5 per post? Several guides from late 2025 and 2026 say so; the Graph API documentation I checked still says 30 hashtags per caption. These conflict, and I could not resolve it from a primary source. Meta can enforce a lower in-app rule than its API states. The practical advice is the same in either case: a caption with five or fewer relevant hashtags is within every figure reported, and long hashtag lists were never useful. ## Why do emoji and Chinese break captions that look short? The platforms count differently. TikTok counts UTF-16 code units, so an emoji outside the basic range counts as two. Threads counts emoji as their UTF-8 bytes, which is usually four each. YouTube measures its description in UTF-8 bytes, where most Chinese characters take three. A 450-character Threads caption heavy with emoji can exceed 500 counted units. When you cross-post text with emoji, trust the tool that counts the way the target platform does. ## How do I check one caption against all of them? Paste it into the [caption character checker](https://schedulepost.fulinlabs.com/tools/caption-length). It compares one caption with the limits of each platform at once, runs in the browser, and nothing you type is uploaded. For a YouTube title and description in particular, use the [YouTube Shorts length checker](/blog/youtube-shorts-title-description-length-2026/), which counts bytes. ## When is this not the right tool? A checker only tells you whether text fits. It does not tell you what to write, and the figures change when a platform updates its rules; the dates above are the dates I checked. If you post to a single platform by hand, the app's own counter is enough. If you schedule through the API, validate the length in your own code before sending, because a rejected caption after the scheduled time is a missed post. See [how to schedule short-form video across platforms](/blog/how-to-schedule-short-form-video-2026/) for the wider workflow. ## Quick checklist - Write to 2,200 characters or fewer for TikTok and Instagram. - Keep a separate YouTube title of 100 characters and a description under 5,000 bytes. - Keep Threads posts to 500 characters and expect emoji to cost more. - Treat unconfirmed claims (4,000-character TikTok captions, 5 Instagram hashtags) as unconfirmed. - See also [video size and aspect ratio for each platform](/blog/short-video-aspect-ratio-size-limits-2026/). ## FAQ ### What is the TikTok caption limit? TikTok's Content Posting API documents a maximum of 2,200 UTF-16 code units for a video caption. Some third-party guides say the TikTok app itself accepts longer captions, about 4,000 characters, but I could not find that in TikTok's own documentation. For a post that goes through a scheduler or API, plan for 2,200. ### What is the Instagram Reels caption limit? Instagram's Graph API documents a caption maximum of 2,200 characters, 30 hashtags and 20 @ tags, and lists no separate figure for Reels. Reports that Instagram cut hashtags to 5 per post in late 2025 conflict with that documentation, and I could not confirm them in a primary source. ### How long can a YouTube Shorts description be? 5,000 bytes, with a 100-character title. The description limit is in bytes, so emoji and Chinese text use it up faster than English. ### How long can a Threads post be? Text in a Threads post is capped at 500 characters, and Meta's documentation says emoji are counted as their number of UTF-8 bytes, so they use more of the limit than they appear to. ### Why does the same caption pass on one platform and fail on another? Each platform sets its own limit and counts differently: characters, UTF-16 code units or UTF-8 bytes. A caption full of emoji or non-Latin text can fit one count and fail another, which is why cross-posting a single caption fails most often on the shortest and strictest platform.