An H1 tag checker analyzes your page's heading structure — verifying that a single H1 tag exists, checking its length, comparing it to your title tag, and showing the full heading hierarchy from H1 through H6. Paste your HTML to get instant analysis.
Paste Your HTML Source
H1 Tag Content
H1 Tag Analysis
Heading Hierarchy Tree
Paste your HTML and click "Check H1 Tags" to see the analysis
How to Use the H1 Tag Checker
The H1 tag checker analyzes your page's heading structure by parsing the HTML with DOMParser and extracting all heading elements (H1 through H6). It checks for the most common SEO heading mistakes — missing H1, multiple H1s, improper heading hierarchy, and H1 length — and displays a visual heading tree so you can verify the outline makes logical sense.
Step 1: Get Your Page's HTML Source
Open your page in a browser and press Ctrl+U (Windows) or Cmd+Option+U (Mac) to view the page source. Copy the entire source code and paste it into the input box above. You can also use browser developer tools: right-click → Inspect → select the HTML element → Copy outer HTML. The tool works with the full page, just the <body> section, or even just a content excerpt.
Step 2: Run the H1 Analysis
Click "Check H1 Tags" to analyze. The tool runs 8 checks: H1 existence, single H1 usage (multiple H1s trigger a warning), H1 length (optimal 20-70 characters), empty H1 detection, keyword overlap with title tag, comparison of H1 and title tag content, heading hierarchy analysis, and heading level counting. Each check shows a pass, warning, or fail badge.
Step 3: Review the Heading Hierarchy Tree
The heading tree shows all headings in document order, indented by level. A healthy tree looks like: H1 → H2 → H2 → H3 → H3 → H2. Problems to look for: H3 appearing before any H2 (skipped level), multiple H1s at the same indent level, H4s with no parent H3. Fixing heading hierarchy improves accessibility for screen reader users and helps Google understand your page's topic structure.
Step 4: Compare H1 and Title Tag
If your HTML contains a title tag, the tool compares it to your H1. The H1 and title should be related but not identical. The title tag is optimized for search results (includes brand name, "Free", CTA suffix) while the H1 is the visible headline for visitors. If they are exactly the same, consider differentiating them slightly — this allows you to target keyword variations in both elements simultaneously.
FAQ
Is this H1 tag checker free?
Yes, this tool is completely free with no account or signup required. You can analyze as many pages as you need. All processing happens in your browser — your HTML is never sent to any server.
Is my HTML data safe when I paste it here?
Absolutely. Your HTML is processed entirely in your browser using JavaScript's DOMParser. It is never uploaded, stored, or transmitted to any server. This tool is safe to use for private, draft, or confidential pages.
Should a page have only one H1 tag?
Yes, best practice is one H1 per page. The H1 is the main headline and tells search engines what the primary topic is. Having multiple H1 tags confuses both search engines and screen readers. In HTML5, technically multiple H1s are allowed per sectioning element, but in practice Google recommends using only one per page.
What is proper heading hierarchy?
Proper heading hierarchy means using heading levels in order without skipping: H1 (page title) → H2 (major sections) → H3 (subsections of H2s) → H4 (subsections of H3s). Skipping from H1 to H3 or starting with H2 breaks the document outline, which can confuse screen readers and may reduce SEO effectiveness.
What is the optimal length for an H1 tag?
The optimal H1 length is 20-70 characters. Too short (under 20 chars) misses opportunities to include keywords naturally. Too long (over 70 chars) can appear spammy and is often truncated in crawl reports. Unlike title tags, H1s have no pixel width limit — but keeping them concise and focused makes them more effective.
Should the H1 and title tag be the same?
They should be related but not identical. The title tag is for search engines and can include 'Free', brand name, or call-to-action suffixes. The H1 is the visible headline for visitors and should match the user's intent. Different wording allows you to target variations of your keyword while keeping both elements optimized.
What does the heading hierarchy tree show?
The heading hierarchy tree displays all h1 through h4 tags found on the page in the order they appear, indented by level. This lets you visually verify that your heading structure makes logical sense — that H3s appear under H2s, that there are no orphaned headings, and that the outline flows in a logical sequence for both users and search engines.