HTML Tag Checker
Check HTML for missing closing tags, unmatched closing tags, and nesting mistakes. Results include source line numbers. This is a tag-balance checker, not a full HTML standards validator.
📈 Averaging 11 uses per day
Start Validating HTML
Paste your HTML code to check for tag errors and validation issues
Before you start
Check for missing closing tags, unmatched closing tags, and incomplete tags. This is a tag-balance check, not a full HTML standards, accessibility, or browser-compatibility validator.
Paste your HTML code here:
Validation Results
Paste HTML code to check its tags.
How to Use HTML Tag Checker
- 1
Paste Your HTML Code
Paste HTML into the text area. The checker updates after a short typing pause, or you can click Check HTML to check immediately.
Tip:You can paste complete HTML documents, code snippets, or individual elements for validation. - 2
Review Validation Results
Review the list of unclosed, unmatched, or incorrectly nested tags with their source line numbers.
Tip:Each error shows the line number and specific issue to help you locate problems quickly in large codebases. - 3
Fix Identified Issues
Use the error messages to fix your HTML code. The tool provides clear descriptions of what's wrong and where the issues are located.
Tip:Common issues include missing closing tags, incorrect nesting, and typos in tag names. - 4
Validate and Re-check
Edit the input to run another tag check automatically. Results from the previous input are hidden while the new check is pending.
Tip:A passing tag check does not confirm HTML standards compliance, accessibility, or browser compatibility.
Features & Benefits
Automatic Tag Checks
Results update after a short typing pause. Use the check button for an immediate result.
Line Number Reporting
Precise error reporting with line numbers to help you quickly locate and fix issues in large HTML documents.
Void and Optional Tags
Recognizes HTML void tags and warns when tags with optional closing tags are left open.
Nested Tag Detection
Identify inner tags left open when an enclosing tag closes.
Error List
Read tag errors and optional-closing-tag warnings alongside source line numbers.
Privacy-First Processing
Validation runs locally; the HTML input is not sent to Hostt's servers.
Frequently Asked Questions
What HTML errors does this tool detect?
It checks for unclosed tags, closing tags without matching openings, nesting mismatches, and incomplete tags. It does not validate tag names, attributes, or every HTML syntax rule.
Does it validate HTML5 specific features?
The tool checks tag structure, nesting, and supported syntax rules. It is a focused structural checker, not a replacement for the full WHATWG or W3C validator.
Can I validate entire HTML documents?
Yes, you can paste complete HTML documents, partial code snippets, or individual elements. The tool will analyze whatever HTML content you provide.
Is my HTML code stored anywhere?
The check runs in your browser. This tool does not upload or save the HTML input.
How accurate is the validation?
This is a focused tag-balance checker. HTML rules for omitted closing tags and valid element nesting are more complex than this check. Use a full standards validator for conformance checks.
Does it validate CSS or JavaScript within HTML?
This tool focuses specifically on HTML tag structure and syntax. It doesn't validate CSS styles or JavaScript code embedded within the HTML document.
Technical Specifications
Use Cases & Applications
Website Development
Find missing closing tags and nesting mistakes in website markup before testing it in a browser.
Email Template Validation
Check tag balance in email templates. Test rendering separately in your target email clients.
Learning HTML Syntax
Students and beginners can use this tool to learn proper HTML syntax and catch common mistakes while building coding skills.
Code Review Process
Use source line numbers to locate tag-balance issues during code reviews.
CMS Content Validation
Check HTML snippets from a CMS for missing or unmatched tags before publishing.
Markup Checks Before Publishing
Find tag-balance issues in page markup. This tool does not assess semantic HTML or predict search rankings.