COMPARE TWO HTML FILES ONLINE
HTML Diff Checker & Code Comparison Tool
Compare two HTML documents line by line, highlight additions and removals, ignore optional whitespace changes and download a readable diff.
Free to useNo sign-upPrivate browser processing
HTML Diff CheckerPrivate line-by-line comparison
Ready to compareUp to 1,200 lines per version
Your side-by-side diff will appear here.
TESTED & REVIEWED
Know what this tool does—and where to double-check
- Reviewed by
- HTML Online Viewer project
- Last reviewed
- Processing
- Ordinary processing happens in this browser tab; the tool does not intentionally upload your source.
- Important limitation
- Automated conversion may not preserve every unusual syntax or application-specific edge case. Keep a backup and test the result in its destination.
WHY USE IT
A focused tool for reliable HTML work
See old and new line numbers together, with unchanged, removed and added source clearly separated.
Ignore whitespace-only changes when formatting differences would otherwise hide the edits that matter.
Both versions stay in your browser and can be exported as a simple unified diff file.
HOW IT WORKS
Three quick steps
- 01Add both versions
Paste the original HTML on the left and the changed HTML on the right.
- 02Choose comparison rules
Decide whether whitespace-only edits should count as changes.
- 03Review or export
Inspect additions and removals by line, then copy or download the diff.
COMMON QUESTIONS
HTML Diff Checker FAQ
Does the HTML diff checker render the pages?
No. It compares source lines so exact markup edits remain visible. Use the main HTML viewer when you also need to compare rendered appearance.
What does Ignore whitespace do?
It treats indentation and repeated spaces as equivalent during matching while preserving the original lines in the displayed result.
Are my HTML files uploaded?
No. The comparison runs locally in your browser.