A YouTube video description can be up to 5,000 characters, and YouTube says to use the first few lines to describe the video, because that's what viewers see before they click to see more. Pick one or two main words that describe the video, put them in both the title and the description, and keep every description unique.
That covers what most people need. The rest is detail from YouTube Help as of Nov 2026: what each part of the box is for, a simple order for writing one, and a couple of features I rarely see anyone use.
The two halves of a description
YouTube says descriptions tell both the algorithm and your viewers what a video is about, and it suggests thinking of the box as two parts. The first part is what shows before a viewer clicks Show more on desktop, or more on mobile. The second part is everything after. Viewers have to click to see the full description, so the opening lines are the only bit you can count on being read.
That's why the opening carries the weight. YouTube calls itself one of the largest search engines in the world and says search terms are matched with the video and the text in the description. So your first lines do two jobs at once: they tell a person whether to watch, and they tell search what the video covers.
| Part of the description | What it's for | What YouTube says |
|---|---|---|
| The first few lines | Saying what the video is about | Use them to describe the video, because they're what viewers see first |
| Everything after Show more | Extra detail about the video and your channel | This part can hold other info about your channel so viewers can learn more |
| Default description | Channel basics that repeat on every upload | Fill out the default description field to show extra info across all your videos automatically |
| Corrections | Fixing a mistake without re-uploading | Add Correction: or Corrections: after any chapters, with the timestamp and explanation on a separate line |
| Hashtags | Being found by people browsing a topic | A hashtag results page shows videos with that hashtag in the title or description |
A simple order for writing one
- Decide the one or two main words that describe the video. YouTube suggests the Research tab in YouTube Analytics and Google Ads Keyword Planner for finding popular keywords and their synonyms.
- Put those words in the title and in the first lines of the description. Titles have a limit of 100 characters, so the description is where you explain.
- Write the opening as a plain answer to what's in the video. YouTube's own tip is to pretend you're searching for the video and ask what you'd type.
- Below the fold, add chapters for longer videos, links to playlists of related videos, credits for collaborators and the people who helped, and your channel profile links if there are links you want to showcase.
- Check how it looks in YouTube search, on the video's watch page and on mobile, and whether the most important information shows where you want it.
Chapters have their own rules, and I've put a ready-made layout in my YouTube chapters template rather than repeat it here. If you're still at the upload stage, uploading a video to YouTube shows where the description box sits.
What the 5,000 character limit means
YouTube's video settings page says descriptions have a limit of 5,000 characters and can't include invalid characters. That's a ceiling, not a target. Nothing in YouTube's tips says longer descriptions do better. What it does say is that every video should have a unique description, which makes it easier to find through search and helps it stand out from similar videos.
So a short, specific description written for this video beats a long block pasted onto every upload. The repeated channel blurb belongs in the default description, which YouTube fills in on every new upload, so you're not copying it across by hand.
Formatting's limited but handy. The box only displays text, but you can bold, italicise or strike through. On mobile, highlight the text to open the editing bar. For a bullet list, start a line with an asterisk, a plus sign or a hyphen, followed by a space. On a computer, the formatting options sit at the bottom of the description box.
Corrections, credits and featured places
Corrections are the feature almost nobody knows about. If you get something wrong in a video, you can add the word Correction: or Corrections: to the description, and YouTube says it has to be in English whatever language the video's in. On a separate line, add the timestamp and a short explanation. The section should come after any video chapters, and viewers then see a View Corrections info card while they watch.
The catch: YouTube says the corrections feature isn't available if your channel has any active strikes, or if the content may be inappropriate for some viewers.
For credits, YouTube's settings page gives a set order for video attributions: the channel name, then the video title, then the video ID. And if your description prominently highlights destinations, the Featured places setting (when available and eligible) can pick them up and show key places in the description or in the Shorts player. You can opt out by unticking Allow automatic Featured places.
Tags, hashtags and the spam line
Tags matter less than most people think. YouTube says a video's title, thumbnail and description are more important for discovery, and that tags mainly help when the subject of your video is commonly misspelled. Otherwise, they play a minimal role.
The bit to watch: YouTube says adding excessive tags to your video description is against its policies on spam, deceptive practices and scams. A wall of keywords at the bottom of the box isn't a clever trick. It's a policy problem.
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Hashtags work differently, because they're read from the description. YouTube says searching or selecting a hashtag shows a results page of videos that include it in either the title or the description. Which ones to use is covered in my guide to YouTube tags and hashtags.
Let your own data pick the words
YouTube points to the How viewers find your report in YouTube Analytics, which shows the search terms people most often use to find your content. Put those next to your description. If people are finding you with words that aren't in it, that's your next edit, and it's based on what your viewers typed rather than a guess.
My verdict
I'd start with the first two lines: say plainly what the video covers, using the one or two words people search for, and make them different from every other video on the channel. Put the channel blurb in the default description so you're not pasting it each time, and use corrections when you get something wrong instead of leaving it.
Skip stuffing tags into the description, because YouTube calls that spam, and skip chasing the 5,000 character limit. Then check the result in search, on the watch page and on a phone, as YouTube suggests.
If you publish videos for a business, deciding what each description needs to carry is part of the content planning I help teams with. I run AI training and workshops for teams, and help businesses with AI enablement and workflow automation, so the busywork runs itself and people get time back. Most of that work is with SaaS marketing teams and small businesses. Here's how we can work together.
Frequently asked questions
How long can a YouTube video description be?
Up to 5,000 characters, and it can't include invalid characters. YouTube doesn't say longer is better; it says each description should be unique.
What should go in the first lines of a YouTube description?
A plain description of the video, including one or two main words that are also in the title. YouTube says the first few lines are what viewers see before clicking Show more.
Do tags in the description help?
Not much. YouTube says tags play a minimal role unless your topic is often misspelled, and adding excessive tags to the description is against its spam policies.
How do I add a correction to a YouTube description?
Add Correction: or Corrections: in English after any chapters, then the timestamp and explanation on a separate line. It isn't available if your channel has active strikes.
Do hashtags in the description work?
Yes. YouTube says a hashtag results page shows videos with that hashtag in either the title or the description.
