YouTube thumbnail size, title, description and video limits
A YouTube thumbnail should be 3840 by 2160 pixels at 16:9, at least 640 pixels wide, as a JPG or PNG under 50 MB from a computer. A title holds 100 characters, a description 5,000 bytes, and a video can run 15 minutes until the account is verified, then up to 12 hours. Here is every limit for regular YouTube videos, from YouTube's own pages. Shorts have a page of their own.
Every number checked against its source on Nov 12, 2026.
YouTube limits at a glance
| Limit | YouTube allows | In PostDaily | Source |
|---|---|---|---|
| Thumbnail size | 3840 × 2160 pixels at 16:9, at least 640 pixels wide (2160 × 3840 for Shorts) | Uses the image you attach to the video post as its thumbnail | YouTube Help: Add video thumbnails |
| Thumbnail file | JPG or PNG; up to 50 MB from a computer or the API, 2 MB from a phone | JPEG or PNG, up to 50 MB within your plan's file size limit | YouTube Data API: Thumbnails set |
| Custom thumbnails | Only on a verified account | Tries to set it, and still publishes the video if YouTube refuses | YouTube Help: Add video thumbnails |
| Title | 100 characters; no < or > | 100 characters; defaults to the post's first line | YouTube Data API: Videos resource |
| Description | 5,000 bytes (UTF-8), so fewer characters with emoji or non-Latin text; no < or > | 5,000 bytes | YouTube Data API: Videos resource |
| Tags | 500 characters for all tags together; commas count, and a tag with a space counts 2 more for its quotation marks | 500 characters together, counted the same way | YouTube Data API: Videos resource |
| Video length | 15 minutes until the account is verified, then up to 12 hours | Checked before publishing against the channel's long-upload status, which PostDaily reads from YouTube | YouTube Help: Upload videos longer than 15 minutes |
| File size per upload | 256 GB or 12 hours, whichever is less | 25 MB on Free, 50 MB on Starter, 100 MB on Pro and 250 MB on Agency | YouTube Help: Upload videos longer than 15 minutes |
| Chapters | First timestamp at 00:00, at least 3 timestamps in order, each chapter at least 10 seconds | Written in the description, which PostDaily sends as typed | YouTube Help: Video chapters |
Thumbnails are 4K now
YouTube's help page now asks for 3840 by 2160 pixels for video thumbnails, with a minimum width of 640, and 2160 by 3840 for Shorts. The long-quoted 1280 by 720 still works, since it is above the minimum, but it is no longer what YouTube recommends. Keep the 16:9 shape so nothing is cropped.
The file limit depends on where you upload: 50 MB from a computer, and through YouTube's API, but 2 MB from the phone app. PostDaily sends thumbnails through the API, so it takes them up to 50 MB, within your plan's per-file limit. On the Free plan that is 25 MB, and a 4K JPG is usually well under it.
Custom thumbnails need a verified account. On an account that isn't verified, YouTube refuses the thumbnail, and PostDaily still publishes the video without it.
Why the description limit is in bytes
YouTube caps a description at 5,000 bytes, not characters. English letters take one byte each, but an emoji takes four and most non-Latin characters two or three, so a description in Japanese or full of emoji fits far fewer characters. PostDaily counts bytes too, so its counter agrees with YouTube. Neither the title nor the description may contain < or >.
Long videos need a verified account
By default YouTube accepts videos of up to 15 minutes. Verifying the account, by text message or voice call, raises that to 12 hours or 256 GB, whichever comes first. PostDaily reads each channel's long-upload status from YouTube and stops a longer video before the upload, with the steps to verify, instead of failing after it.
Uploads through PostDaily are capped per file by plan: 25 MB on Free, 50 MB on Starter, 100 MB on Pro and 250 MB on Agency. Long, high-bitrate videos are better uploaded in YouTube Studio. How to schedule YouTube videos covers both routes, and Shorts have their own limits.
Common questions
- What size should a YouTube thumbnail be?
- YouTube asks for 3840 × 2160 pixels at 16:9, with a minimum width of 640 pixels, as a JPG or PNG.
- What is the maximum YouTube thumbnail file size?
- 50 MB from a computer or through YouTube's API, and 2 MB from the phone app.
- What is the YouTube title character limit?
- 100 characters, and a title can't contain < or >.
- How long can a YouTube description be?
- 5,000 bytes. Emoji and non-Latin characters take two to four bytes each, so they fit fewer characters.
- How long can a YouTube video be?
- 15 minutes until the account is verified, then up to 12 hours or 256 GB, whichever comes first.