HTML headings are H1–H6 tags that define the content hierarchy on a page. Search engines and screen readers use them to understand the document structure. A correct heading structure is crucial for SEO, accessibility and page readability.
Check your page's heading structure
The tool will automatically analyze the heading hierarchy of any page: Headings Checker.
What are HTML headings?
Headings are HTML tags from H1 to H6 that create a hierarchical content structure — similar to chapters and subchapters in a book. H1 is the main title, H2 are sections, H3 are subsections etc. The browser displays them with decreasing font size by default, but their true role goes far beyond appearance.
H1–H6
6 heading levels
1×
recommended number of H1 per page
~60%
of pages have heading errors
WCAG
requires a correct hierarchy
H1–H6 heading hierarchy
Each heading level serves a different role in the document structure. Skipping levels (e.g. going from H2 to H4) is a structural error.
One per page. Main keyword. Describes the entire page.
Main content divisions. Should cover the key topics of the page.
Elaboration of the H2 section. May contain LSI keywords.
Less commonly used. Use only when the content requires a deeper division.
Very rare. Most often unnecessary — consider simplifying the structure.
Practically unused. In most cases it can be replaced with another HTML element.
Example of a correct structure
A correct heading hierarchy forms a tree — each level is nested within the parent.
H1 DNS guide
H2 What are DNS records?
H3 A record
H3 CNAME record
H2 How to check DNS?
H3 Online tools
H3 dig command
H1 DNS guide
H3 What are DNS records? ← H2 skipped
H5 A record ← H4 skipped
H2 How to check DNS? ← H2 after H5?
H4 Online tools ← missing H3
Headings and SEO
Search engines analyze headings to understand what the page is about and how important individual content sections are.
H1 — the most important SEO signal
Google treats H1 as the main description of the page. It should contain the main keyword and be unique — one H1 per page. Missing H1 or multiple H1s is a signal of poor structure.
H2 — section topics
H2s define the main topics discussed on the page. It is worth including variants and synonyms of the main keyword (LSI keywords) in them. They often appear in featured snippets.
H3–H6 — depth and detail
H3 and deeper help robots understand the detailed structure. They are particularly important for long guide articles and documentation. They have less direct impact on rankings than H1 and H2.
Headings and accessibility
For screen reader users (blind, visually impaired), headings are the primary way of navigating a page.
WCAG 2.1 standard requires a correct heading hierarchy
Criterion 1.3.1 (Info and Relationships) and 2.4.6 (Headings and Labels) require the use of headings in a way that reflects the content structure, not just the visual appearance.
Best practices
- One H1 containing the page topic
- Maintaining hierarchy continuity (without skipping levels)
- Descriptive, understandable heading content
- Headings reflect structure, not style
Common mistakes
- Using headings only for large font size
- Skipping a level (e.g. H2 → H4)
- Missing H1 or multiple H1s on the page
- Empty headings or headings with only an image
Quick summary — H1–H6
| Tag | How many per page | SEO impact | Typical use |
|---|---|---|---|
| H1 | Exactly 1 | Very high | Page / article title |
| H2 | A few | High | Main content sections |
| H3 | Any | Moderate | Subsections within H2 |
| H4 | Any | Low | Deeper content divisions |
| H5 | Rarely | Minimal | Documentation, specifications |
| H6 | Almost never | Minimal | Very rare cases |
FAQ
Technically HTML5 allows multiple H1s in different sections, but in SEO practice one H1 per page is recommended. Google has repeatedly confirmed that it prefers one clear declaration of the page topic. Multiple H1s can dilute the signal for search engines and confuse screen reader users.
No. The title tag is invisible on the page — it appears in the browser tab and in Google results. H1 is the visible heading on the page. They should be similar in content, but do not have to be identical. The title is limited to about 60 characters for search results, H1 can be longer.
Yes. Google analyzes the heading hierarchy to understand the structure and thematic relationships of the content. Skipping levels (e.g. H2 → H4) is not a critical error, but it makes it harder for robots and users to understand the relationships between sections. Regular audits of heading structure are a good SEO practice.
Yes — you can change the appearance of a heading freely via CSS. However, what matters is the semantic role in HTML, not the visual one. The reverse situation is problematic: styling a regular paragraph as large text does not make it a heading for search engines or screen readers.
You can use our Headings Checker tool, which visually represents the heading hierarchy of any page. Alternatively, in Chrome DevTools, enter into the console: document.querySelectorAll('h1,h2,h3,h4,h5,h6'), to see a list of all headings.