Check a YouTube title, description and tags against the real limits

The three limits, and where they come from

These are not folklore. They are the constraints YouTube publishes on the videos resource of its own Data API, which is the interface every upload ultimately goes through:

• Title: 100 characters, and it “may contain all valid UTF-8 characters except < and >”.
• Description: 5,000 bytes — bytes, not characters — with the same restriction on angle brackets.
• Tags: 500 characters in total across every tag, with a counting rule of its own that is described below.

Two of those three are counted in a way a plain character counter gets wrong, which is the reason this page exists rather than a length call in a text editor.

The description limit is in bytes, and that is not pedantry

UTF-8 spends one byte on an ordinary Latin letter, two or three on most accented and non-Latin characters, and four on a typical emoji. So a 5,000-character description written in English fits, and a 5,000-character description in Japanese is roughly three times over the limit and will be refused. A creator dropping a dozen emoji into a description spends about fifty bytes of the budget on them.

Most counters report characters, so they tell you there is room right up until the upload fails. This one counts the bytes YouTube counts, and when the two numbers differ it says so and shows both, so you can see where the difference is coming from instead of guessing.

The tag rule almost nothing implements

The 500-character tag budget is not the sum of your tags' lengths. YouTube documents that it “calculates limits uniquely for this field”, and two things count that you would not expect:

The commas count. Ten tags means nine separator characters out of your 500.

A tag containing a space is treated as quoted text. YouTube's own example is exact: Foo Baz counts as 9 characters, because the quotation marks are counted too, while Foo-Baz counts as 7. Every multi-word tag therefore costs two characters more than it looks like it should — and a list of twenty multi-word tags has quietly spent forty characters on punctuation that is never displayed anywhere.

This checker applies that rule, so the number it shows is the number YouTube will apply. It also tells you how many of your tags contain spaces and what they are costing you, in case you want to hyphenate a few and buy the room back.

Angle brackets are refused outright

< and > are not allowed in a title or a description, in any position. They are typed more often than you would expect — pasting from a document that used them as quotation marks, or writing something like <30 seconds — and the upload is rejected rather than sanitised. The checker flags them separately from the length, because a description that is well inside 5,000 bytes will still fail on one stray bracket.

The truncation advice, labelled honestly

Everyone will tell you a YouTube title should be about 60 characters. That number is not a YouTube rule and YouTube does not publish a truncation point: what gets cut depends on the surface, the device width, and how wide your particular letters happen to be. “WWW” and “lll” do not occupy the same space.

So this tool separates the two clearly. The bar measures the real, documented 100-character limit. Past roughly 60 characters it adds a note saying titles are commonly cut off in search and suggested videos — flagged as guidance, not as a rule, because a checker that presents an estimate with the same confidence as a published constraint has taught you something false.

The same applies to descriptions: only the opening lines show before “Show more”, so the checker points out a very long first line. Front-load anything that has to be read.

What this checker does not do

It does not call the YouTube API, so it cannot tell you whether a title is already taken, how a video is performing, or what a keyword's search volume is. It gives no SEO score — nobody outside YouTube knows the ranking function, and a number invented to look authoritative is worse than no number. It does not write or rewrite anything, and it does not store what you type. Reload the page and it is gone.

It is also worth knowing what tags are worth. YouTube's own guidance is blunt: title, thumbnail and description matter more, tags “play a minimal role” in discovery, and they are mainly useful when your subject is commonly misspelled. Staying under 500 characters is a correctness problem, not a growth strategy.

Once the metadata is right

Hermoso publishes to YouTube as well as making the video: scheduling, the 100-character title and 5,000-character description caps enforced when you schedule rather than at upload time, thumbnails, comment handling and per-video analytics. The channel's full rules are on the YouTube scheduler page. If the video itself is what is missing, the AI video ad maker and the faceless video ad maker are the two places to start, and the caption for every other network can be checked at once with the caption length checker.

Frequently asked questions

How long can a YouTube title be?

100 characters. That is the hard limit YouTube documents on its Data API's video resource, and an upload over it is refused. Separately — and this is advice, not a rule — titles past roughly 60 characters are commonly cut off in search results and suggested videos. YouTube does not publish a truncation point, because it depends on the surface, the device width and how wide your particular letters are, so this checker measures the real 100 and flags the 60 as guidance.

How long can a YouTube description be?

5,000 bytes, not 5,000 characters. UTF-8 spends one byte on an ordinary Latin letter but two or three on most accented and non-Latin characters and four on a typical emoji, so a description in Japanese can be roughly three times over the limit at 5,000 characters. Counters that measure characters tell you there is room right up until the upload fails; this one counts the bytes YouTube counts and shows both numbers when they differ.

What is the YouTube tag limit?

500 characters for all tags combined, and YouTube counts them in a way most tools do not implement. The commas between tags count toward the total, and a tag containing a space is treated as quoted text — YouTube's own example is that "Foo Baz" costs 9 characters while Foo-Baz costs 7. So every multi-word tag costs two characters more than it appears to. This checker applies that rule and tells you how much your multi-word tags are costing.

Why is my title rejected when it is under 100 characters?

The most common cause is an angle bracket. YouTube does not allow < or > in a title or a description at all — they arrive by pasting from a document that used them as quotation marks, or by writing something like "<30 seconds" — and the upload is refused rather than cleaned up. This checker flags them separately from the length, because a title well inside the limit will still fail on one stray bracket.

Do YouTube tags still matter for ranking?

Barely, on YouTube's own account. Its help documentation says the title, thumbnail and description are the more important metadata for discovery, that tags play a minimal role, and that they are mainly useful when the content of a video is commonly misspelled. It also treats excessive tagging in a description as spam. Staying inside the 500-character limit is a correctness question, not a growth strategy.

Does this send my title or description anywhere?

No. The counting happens in your browser; there is no API call, no analytics event carrying your text and nothing stored. Reload the page and everything you typed is gone, because no copy of it existed anywhere but in the tab.

Does it score my title for SEO?

No, deliberately. Nobody outside YouTube knows how its ranking works, and a score invented to look authoritative is worse than no score at all. This tool only reports things that are true: the documented limits, the way YouTube counts against them, the characters it refuses, and one clearly-labelled note about where titles tend to get visually cut off.