Check the H1 to H6 heading structure

For developers and editors reviewing a document’s heading logic before publication, migration or redesign.

Unfold the H1 to H6 hierarchy of an HTML document and immediately see missing, reversed or poorly ordered heading levels.

How to use

Paste an HTML fragment into the input area, or import a supported text file that contains the markup you want to inspect.
Run the extraction to display the heading hierarchy from H1 through H6 in document order.
Review the outline and look for missing levels, reversed ranks or headings that jump ahead without a clear reason.
Fix the source HTML, run the extraction again, and compare the new outline with the earlier result.

Example

With the sample fragment, the tool should show an H1 followed by an H2, an H3 and another H2. Check the indentation and sequence to confirm that the outline stays logical and that no heading rank is skipped unexpectedly.

Input

<h1>Reference guide</h1><h2>Installation</h2><h3>Requirements</h3><h2>Usage</h2>

Limits and formats

It does not judge whether the heading text is useful, well written or suitable for search visibility.
It will not repair invalid HTML and does not replace a full validation before publication.
Headings added by scripts after page load may be missing if you only provide the initial source code.

Where processing happens

The check runs entirely in your browser. The code you paste or import stays on your device and is not sent anywhere while you review the outline.

Frequently asked questions

What can I do with a heading outline?

You can see how H1 to H6 tags are ordered in an HTML fragment. That helps you find a broken hierarchy before publishing, migrating or handing the document to another contributor.

Can I inspect a whole page?

Yes, if you paste its HTML or import an accepted text file. The tool only uses the content you provide; it does not download an address or run the page scripts.

What does a missing level mean?

It means the outline moves from one heading rank to a later one without the level in between, such as H2 to H4. The page may still work, but the structure is worth reviewing.