Heading Structure Checker — free online
You wrote a page, but are the headings in the right order? A second H1 sneaks in, an H2 jumps straight to an H4, and screen readers and search engines quietly get confused. It's hard to spot by eye. We added a free tool that does it for you — Heading Structure Checker — right in your browser.
What it does
Paste any HTML and it lays out your heading hierarchy as a clean indented tree, so you can see the shape at a glance. It flags the common problems too: more than one H1, levels that get skipped, and headings left empty.
Nothing leaves your device
The whole thing runs in your browser. Your HTML is never uploaded anywhere and nothing is saved. When you close the tab, it's gone.
How to use it
- Open Heading Structure Checker and paste your HTML into the box.
- Look over the indented tree and read any flagged issues.
- Fix the headings in your page and paste again to check.
It's free with no limit. There are more small tools on the Apps page.