Does your caption fit everywhere?

One caption, three platforms. Characters, hashtags and mentions counted the way each one's API counts them — which is not the same way.

Runs in your browser. Nothing is uploaded, no signup.

Caption checker
Hashtags and @ mentions you type show up here.

TikTokCaption · Direct Post API

  • Length 10 / 2,200 UTF-16 units

    An emoji counts 2, sometimes more.

  • Hashtags 10

    No published cap; they count in the length.

InstagramReel caption

  • Length 20 / 2,200 characters
  • Hashtags 30 / 5

    Five since Dec 2025, rolled out gradually; the API page still says 30.

  • @ mentions 20 / 20

YouTubeTitle and description

  • Title 40 / 100 characters

    Add a title above to check it.

  • Description 40 / 5,000 bytes

    Bytes, not characters: é counts 2, an emoji 4.

  • Hashtags 50 / 60

    Up to 3 of them may show by the title.

Watch an example

13 seconds · a made-up example

The studio writes a caption for every video, in each account's language.Join the beta

How it works

Short and checkable: every limit links to the platform's own page, read on 28 Oct 2026.

  1. Each platform counts in its own unit

    TikTok's posting API counts the caption in UTF-16 units, so most emoji count two. YouTube's API counts the description in bytes, so an accented letter counts two and an emoji four. Instagram says characters; the checker counts each character once.

  2. Hashtags have their own limits

    Instagram moved to five hashtags per post and reel from December 2025 (its API page still lists 30, so five is the safe number). YouTube ignores every hashtag on a video that has more than 60, and may show up to three by the title. TikTok publishes no hashtag cap: they simply count in the length.

  3. YouTube refuses two characters

    The YouTube Data API accepts any character in a title or description except < and >. The checker flags them, and the title's 100-character limit.

What it doesn't do

  • It doesn't judge the caption itself — hook, tone or keywords are yours.
  • It doesn't know where each app cuts the caption with "more": that changes with the screen and isn't published.
  • Nothing you type is sent or saved.

Questions

How long can a TikTok caption be?

2,200 UTF-16 units through TikTok's posting API, hashtags and mentions included. An emoji counts 2, sometimes more.

How many hashtags can I use on Instagram?

Five per post and Reel since December 2025 (rolled out gradually). The API page still says 30.

How long can a YouTube title and description be?

100 characters for the title and 5,000 bytes for the description — bytes, so an accented letter counts 2 and an emoji 4. Over 60 hashtags, YouTube ignores all of them.

Sources

  1. 1TikTok for Developers — Content Posting API — Direct Post referenceupdated 27 Oct 2026 · read 28 Oct 2026
  2. 2Meta for Developers — Instagram API — IG User Media, Reel specifications and captionAPI v26.0 · read 28 Oct 2026
  3. 3Social Media Today — Instagram limits captions to five hashtags, posts and reels18 Dec 2025 · read 28 Oct 2026
  4. 4YouTube Data API — videos resource — title, description and tags limitsupdated 15 Oct 2026 · read 28 Oct 2026
  5. 5YouTube Help — Hashtags: more than 60 and all are ignoredup to 3 shown by the title · read 28 Oct 2026

More free tools

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One idea, every account.

Vertiscale writes each video with its caption, makes a version for each of your accounts, and you approve every one before it goes out.

Join the private beta Free during the beta, no card.