HTML Validator — Check Unclosed Tags
Paste HTML and press “Check HTML” to see problems listed by line number.
Your text and files never leave your browser — nothing is sent to a server.
How to use
- Paste your HTML, or click “Try an example”, then press “Check HTML”.
- Findings are listed by line with [Error], [Warning] or [Info]. Errors are structural problems that can break the layout; warnings are worth fixing.
- With “Scope” on Auto, missing DOCTYPE, lang, title, charset and viewport are only checked when the input contains <html> or <!DOCTYPE>. Choose “Fragment” for partial snippets.
- Elements whose end tag is optional, such as <p>, <li> and <td>, are not reported when left open.
FAQ
Will the results match the W3C validator?
Not always. This tool is a lightweight check of basic structure: tag pairs, duplicate ids and missing essentials. To verify every rule about allowed attributes and children, also run the W3C validator at validator.w3.org.
Why are unclosed <p> or <li> tags not errors?
The HTML standard lets elements such as <p>, <li>, <td> and <option> close automatically when the next one starts, so their end tags are optional. Elements like <div>, <span> and <b> must be closed, so missing end tags there are reported.
Is my HTML uploaded?
No. The check runs entirely in your browser and nothing is sent anywhere.
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