Why the YouTube Tags Character Limit Charges You for Quotes and Commas

What is the YouTube tags character limit?

Google sets the YouTube tags character limit at 500 characters for the entire tag list on a video, and it counts commas and implied quotation marks toward that total. The rule lives on the snippet.tags[] property of the videos resource in the YouTube Data API reference, which reads: "A list of keyword tags associated with the video. Tags may contain spaces. The property value has a maximum length of 500 characters." The 500 is a budget for the whole list. No single tag has its own cap, and YouTube documents no maximum number of tags.

The same videos resource sets the other two text limits on an upload, in different units.

Field	Documented limit	Unit	API property
Tag list	500	characters	snippet.tags[]
Video title	100	characters	snippet.title
Video description	5000	bytes	snippet.description

The description is the odd one out, measured in bytes, and our breakdown of the YouTube description character limit covers that unit.

How does YouTube count characters in the tag list?

YouTube counts every letter in every tag, plus one character for each comma between tags, plus two characters for the quotation marks around any tag that contains a space. The API reference spells out both extra charges under the property description:

"The property value is a list, and commas between items in the list count toward the limit. If a tag contains a space, the API server handles the tag value as though it were wrapped in quotation marks, and the quotation marks count toward the character limit. So, for the purposes of character limits, the tag Foo-Baz contains seven characters, but the tag Foo Baz contains nine characters."

Foo-Baz and Foo Baz are both seven keystrokes. The spaced one costs 9, because the server counts it as "Foo Baz".

The comma charge applies even when you never type a comma. Through the API you send tags as a JSON array, and the server still adds one character for every gap between items. A list of 20 tags carries 19 commas you never see.

Put together, the formula for a tag list is short:

1. Add up the letters, digits, spaces and punctuation in every tag.
2. Add 2 for each tag that contains at least one space.
3. Add the number of tags minus 1, for the commas.
4. Compare the result against 500.

A tag with three spaces still costs only 2 extra. The quote charge applies once per tag, not once per space.

How many characters does a real tag list use?

A real tag list uses more characters than its letters, and the gap grows with every multi-word tag. Take six tags a bread channel would put on a starter tutorial.

Tag	Letters and spaces	Quote charge	Cost
sourdough	9	0	9
sourdough starter	17	2	19
sour dough	10	2	12
how to feed a sourdough starter	31	2	33
no knead bread	14	2	16
levain	6	0	6
Commas between 6 tags			5
Total	87	8	100

A counter that adds up the tags as typed reports 87. YouTube charges 100, a 15 percent markup on six tags. The sour dough tag is there on purpose, because misspellings are the one job YouTube says tags do well.

How many tags fit in 500 characters?

The number of tags that fit in 500 characters depends on tag length and on how many tags contain spaces, so no fixed count exists. The formula gives exact answers for any list, and a few shapes show the range.

Tag list shape	Cost per tag	Commas	Total for the list	Fits?
20 single-word tags, 24 letters each	24	19	499	Yes
20 two-word tags, 22 letters and spaces each	24	19	499	Yes
20 two-word tags, 23 letters and spaces each	25	19	519	No
21 two-word tags, 20 letters and spaces each	22	20	482	Yes
50 single-word tags, 9 letters each	9	49	499	Yes

Rows two and three show how thin the margin is. One extra letter per tag across 20 multi-word tags pushes the list from 499 to 519. That is how a list your notes app counts at 460 characters gets rejected at 519.

The last row is legal and still a bad idea, for reasons YouTube's help pages give.

Do YouTube tags still matter for discovery?

YouTube tags matter less than the title, thumbnail and description, and YouTube says so on its help page for adding tags: "Your video's title, thumbnail, and description are more important pieces of metadata for your video's discovery." The same page names the case where tags earn their place: "Tags can be useful if the content of your video is commonly misspelled. Otherwise, tags play a minimal role in your video's discovery."

I read that as a spending rule for the 500 characters. Spend them on the misspellings and alternate spellings people type into search, such as sour dough next to sourdough, and on terms that do not fit naturally in the title. Do not spend them on 40 near-duplicates of the title. The help page adds a warning about the other direction: "Adding excessive tags to your video description is against our policies on spam, deceptive practices, and scams."

A keyword you care about belongs in the title first, then the opening lines of the description, where YouTube's text formatting rules decide what renders.

What is the difference between YouTube tags and hashtags?

YouTube tags are hidden keywords in the tag field, and hashtags are visible # words in the title or description that link to a hashtag results page. They draw from different budgets. Tags count against the 500 character tag limit. Hashtags count against the title's 100 characters or the description's 5000 bytes.

YouTube's hashtag policy page sets its own rules for the visible kind. "Out of all the hashtags you add to the video's description, up to three hashtags that are considered most engaging will appear by your video title." It also sets a hard stop: "If a video or playlist has more than 60 hashtags, we'll ignore each hashtag on that content." The same page closes the loophole of pasting a tag list into the description: "adding ordinary descriptive tags or repetitive sentences in the description is (still) prohibited."

A tag list that will not fit in 500 characters does not belong in the description either. Our explainer on what a hashtag is covers hashtags on the other networks.

What happens when the tag list goes over 500 characters?

An upload whose tag list breaks the 500 character rule fails, and the error the videos.insert reference lists for bad tags is invalidTags with a 400 Bad Request status. The error table describes it as "The request metadata specifies invalid video keywords." That text names neither the limit nor the counting rule, so a developer who never read the property note gets no hint that commas and quotes pushed the list over.

A 400 rejects the whole insert request, not just the tags, so a scheduled upload misses its slot until someone shortens the list and sends it again. If you publish through the API on a schedule, our guide to scheduling a video through the YouTube API walks through the rest of the upload request.

When a tag list breaks the 500 character limit

1

The count comes in high. A list of 20 two-word tags at 23 letters and spaces each totals 519 characters, over the 500 limit.

2

The insert request fails. videos.insert returns a 400 Bad Request with the error invalidTags.

3

The whole request is rejected. Not just the tag field, the entire upload fails.

4

The scheduled slot is missed. The upload waits until someone shortens the list and sends it again.

How do you trim a YouTube tag list to fit?

Trim a YouTube tag list by counting it the way the API does, then cutting the tags that duplicate the title before you cut the misspellings.

1. Paste the list into a spreadsheet, one tag per row.
2. In the next column, compute the length of each tag and add 2 when the tag contains a space.
3. Sum that column, then add the number of rows minus 1.
4. If the total is over 500, delete tags that repeat words already in the title first.
5. Replace spaced tags with single words where the meaning survives. nokneadbread does not survive, so keep no knead bread and cut elsewhere.
6. Keep common misspellings and alternate spellings to the end. Those are the tags YouTube's help page says are useful.
7. Aim a few characters under 500, so a last-minute edit to one tag does not tip the list over.

A spreadsheet formula such as =LEN(A2)+IF(ISNUMBER(SEARCH(" ",A2)),2,0) does step 2 in one pass.

How does AdaptlyPost handle YouTube tags?

AdaptlyPost lets you set tags on a YouTube video along with its title, description, thumbnail and publish time, and then publishes it to the connected channel on schedule. The YouTube video scheduler covers the dashboard flow, and the YouTube video upload API documents the programmatic one. On the API, youtubeConfigs.tags accepts up to 20 tags, and a request with more than 20 tags, or a videoTitle over 100 characters, comes back as a 400 on the create call before any post exists. The 20-tag cap is AdaptlyPost's. The 500 character budget with its comma and quote charges is YouTube's, and it applies on top. Twenty long multi-word tags can pass the first check and still break the second, so run the count above before you schedule. The same metadata rules apply when you schedule YouTube Shorts.

Frequently asked questions

Is the YouTube tag limit 500 characters per tag or for all tags?

The 500 character limit covers the whole tag list on a video. The YouTube Data API documents it on the snippet.tags[] list property, and no single tag has a separate cap.

Do commas count toward the YouTube tags character limit?

Yes. The API reference states that "commas between items in the list count toward the limit." A list of 20 tags carries 19 commas, which cost 19 characters even when you send the tags as a JSON array and never type a comma.

Why does a tag with a space cost two extra characters?

The API server treats any tag containing a space as though it were wrapped in quotation marks, and those two marks count toward the 500. The reference gives the example that Foo-Baz costs 7 characters and Foo Baz costs 9. The charge is 2 per tag, however many spaces the tag has.

How many tags can a YouTube video have?

YouTube documents no maximum tag count, only the 500 character budget for the list. Fifty short single-word tags fit, and twenty long multi-word tags do not. AdaptlyPost's API adds its own cap of 20 tags per video.

What error does YouTube list for invalid tags?

The videos.insert error table lists invalidTags, a 400 Bad Request described as "The request metadata specifies invalid video keywords." The whole upload request fails. The message does not mention the 500 limit or the comma and quote charges.

Are YouTube tags worth adding at all?

Tags are worth adding for misspellings and alternate spellings of your topic. YouTube's help page says tags "can be useful if the content of your video is commonly misspelled" and otherwise "play a minimal role" in discovery. Put your main keyword in the title and description first.

How do you count a tag list's characters before uploading?

Paste the tags into a spreadsheet, one per row, and compute each tag's length plus 2 for any tag with a space. Sum that column, then add the number of tags minus one for the commas. A formula like =LEN(A2)+IF(ISNUMBER(SEARCH(" ",A2)),2,0) handles the length and the quote charge in one pass. Aim for a total a few characters under 500, so a small edit doesn't push the list over.

Is AdaptlyPost's tag limit the same as YouTube's 500 character budget?

No, AdaptlyPost's API caps a tag list at 20 tags, a limit separate from YouTube's 500 character budget. Both apply at once, so a request with more than 20 tags fails before a post even exists, and a list of 20 tags that passes that check can still break YouTube's 500 character rule through commas and quotes. Twenty long multi-word tags are the shape most likely to hit both limits.

Should a target keyword go in the tags or the title?

The title first, then the opening lines of the description, where YouTube's text formatting rules decide what renders. YouTube's own help page ranks title, thumbnail and description above tags for discovery. Tags are the place for misspellings and alternate spellings, not for the main keyword.

Do the tag list rules apply to YouTube Shorts scheduled through AdaptlyPost?

The same metadata rules apply when scheduling YouTube Shorts through AdaptlyPost as for regular videos. The 500 character tag budget, the comma and quote charges, and AdaptlyPost's 20-tag cap all carry over unchanged.