Clear line changes
Color-coded output makes structural edits easy to scan.
Diff Checker
Compare two blocks of text line by line and review additions and removals.
Private by defaultYour inputs and files are processed on this device.
Free and instantNo account, queue, or software installation required.
Ready to useCopy or download results as soon as they are generated.
How to use Diff Checker
Get a reliable result in three straightforward steps.
Add both versions
Place the original on the left and the changed text on the right.
Run the comparison
Matching lines are aligned while removed and added lines are classified.
Review the diff
Use red removals and green additions to audit the change.
Built for everyday work
Useful without the busywork
Focused controls, immediate feedback, and no account between you and the result.
Addition summary
See the number of inserted and removed lines immediately.
Private comparison
Contracts, configuration, and drafts stay on your device.
Practical guide
What is Diff Checker?
A diff checker compares two versions of text and identifies lines that were added, removed, or left unchanged. It is useful when revision tracking is unavailable or when values come from separate files and systems.
This page uses a line-based longest common subsequence comparison. It favors understandable structural changes rather than character-level editing marks.
Practical applications
When to use this tool
Common ways Diff Checker fits into real projects and daily tasks.
Code review
Compare snippets, configuration files, and generated output.
Document revisions
Audit changed paragraphs in two plain-text drafts.
Data checks
Find missing or newly added lines in exports.
Copy verification
Confirm whether published text matches an approved version.
Helpful answers
Frequently asked questions
Quick answers about diff checker and how this page works.
Is the comparison character by character?
No. It compares complete lines to keep larger revisions readable.
What do the colors mean?
Green lines exist in the changed version; red lines were present only in the original.
Why is there a line limit?
Diff comparison grows more expensive as both documents grow, so a guard keeps the browser responsive.
Are my documents uploaded?
No. Both inputs are compared locally.