H1 Tag Checker
Two H1 tags on one page is one of the most common on-page mistakes, and it is invisible until something checks for it.
Free · No sign-up · Reads the raw HTML a crawler sees
One H1, and why the rule survives
HTML5 technically permits multiple H1 tags, one per sectioning element, and Google has said several H1s will not hurt you. Both are true, and one H1 is still the better call.
The reason is that no browser or screen reader ever implemented the HTML5 outline algorithm. Assistive technology treats headings as a flat list, so a second H1 reads as a second page title. And in practice a duplicate H1 is almost never intentional — it is a logo wrapped in a heading, or a template that emits one alongside the content.
We hit this ourselves: running this tool against a site we were studying turned up two H1 tags on its homepage, one of them the logo.
What a good H1 looks like
It states what the page is about, in words a person would use. It sits near the top of the source. It agrees with the title tag without necessarily matching it word for word.
AI engines lean on it more than Google does. When an engine summarises your page, the H1 is the label it starts from — which makes a logo-as-H1 actively costly rather than merely untidy.
How to use it
- Enter the page URL — Any public page.
- Check the count — One is right. Zero and two are both worth fixing.
- Read the outline — The full heading list shows where a stray H1 came from.
Frequently asked questions
How many H1 tags should a page have?
One. Multiple H1s are valid HTML and will not earn a penalty, but assistive technology treats them as competing page titles and duplicates are almost always accidental.
Does the H1 need to match the title tag?
They should describe the same thing but do not have to be identical. The title often carries a brand suffix the H1 does not need.
Is it bad to put my logo in an H1?
Yes. It spends your strongest heading on your company name and tells summarisers the page is about your brand rather than its actual subject.