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Text Tools · Updated October 20, 2026

Compare Two Texts

You can compare two texts line by line in your browser and see every added, removed and unchanged line, with a summary of the changes and optional ignore-case and ignore-whitespace toggles.

Runs in your browserFree · No sign-up · No watermark
TEXT ↔ TEXTRuns in your browser
Loading the tool…

Everything runs locally in this tab. No file is uploaded while the tool loads.

This tool runs in your tab. Nothing is uploaded and no copy is stored.

How files are handled

At a glance

Works with
TEXT ↔ TEXT
Processing
In your browser
Price
Free, no account
Updated
October 20, 2026
All Text Tools

About Text Diff

Comparing two versions of the same text by eye is slow and unreliable, especially when a paragraph has been reworded, a clause has moved or a line has disappeared somewhere in the middle. This tool lines up both versions and marks the exact lines that differ, then reports how many lines were added, removed and left unchanged.

The comparison uses a longest common subsequence, the same family of algorithm behind version control diffs, so lines are matched by content rather than by position. That keeps one inserted sentence from marking the whole rest of the document as changed, and the ignore-case and ignore-whitespace options stop formatting noise from hiding the real edits.

What this tool does

The details that matter when you use Text Diff for real work.

  • Real LCS line diff

    The tool computes a longest common subsequence and reports the fewest possible added and removed lines instead of comparing line 1 with line 1.

  • Markers plus text labels

    Added lines carry a + and removed lines a −, and screen readers announce Added line or Removed line, so the result never relies on color alone.

  • Change summary

    Three counters show the number of added, removed and unchanged lines so you can judge the size of an edit at a glance.

  • Ignore case and whitespace

    Turn on either option to treat Hello and hello, or different indentation, as the same line, and the result updates with one click.

  • Line numbers on both sides

    Every row shows its original and updated line number, with the gap left blank where a line exists on only one side.

  • Copy the whole diff

    Copy the result as a unified diff with plus, minus and space prefixes for pasting into a ticket, email or review comment.

How to use Text Diff

No account, no installation — the whole job happens in this browser tab.
  1. 01

    Paste the original text

    Put the first version in the left box; each line break starts a new line in the comparison.

  2. 02

    Paste the updated text

    Put the changed version in the right box. Comparing against an empty box shows every line as added or removed.

  3. 03

    Choose which differences matter

    Tick Ignore case, Ignore whitespace differences, or both, so only meaningful edits are reported.

  4. 04

    Compare the two texts

    Press Compare texts and read the summary above the line table.

  5. 05

    Review the marked lines

    Go through the + and − rows, then copy the diff if you need to share it.

How this tool works

Works with
TEXT ↔ TEXT
Processing
Client-side, in your browser. Nothing is uploaded.
Requirements
Chrome, Edge, Firefox or Safari · JavaScript enabled

Limitations worth knowing

  • The comparison is line based, so an edit inside a long line is shown as a removed line plus an added line rather than as word-level highlights.
  • Each side is capped at 4,000 lines; longer input is compared on its first 4,000 lines and the result says so.
  • Very different texts can produce thousands of rows; the line table scrolls, but a word-level diff is easier for reviewing a fully rewritten draft.

Privacy and file handling

Both texts and the comparison stay in this browser tab. The diff is computed with JavaScript on your device, so nothing is uploaded, stored or logged, and closing the page discards the input and the result.

Read the full privacy policy

Text Diff FAQ

Short, direct answers to the questions people ask before using this tool.
How does this text diff decide which lines changed?
It computes a longest common subsequence of the two line lists, then walks that alignment to mark lines as unchanged, removed or added. Because matching is based on line content, inserting one line near the top does not shift every following line into a change.
What do the + and − markers mean?
A + marks a line that exists in the updated text but not in the original, and a − marks a line that was removed from the original. Unmarked rows exist in both versions, and each marked row also has a screen reader label and a line number on the side where it exists.
What do the ignore case and ignore whitespace options do?
Ignore case treats Hello, HELLO and hello as the same line. Ignore whitespace collapses runs of spaces, tabs and trailing spaces before comparing, so reindented or reformatted text is not reported as changed. Both options affect only the comparison, never the text you see.
Can the tool compare words or characters instead of lines?
No, the comparison is line by line. A reworded sentence inside a line appears as one removed line and one added line rather than a highlight on the changed words, which is enough for spotting edits but less detailed than a word-level diff.
How long can the texts be?
Each side is compared up to 4,000 lines. Longer texts are compared on their first 4,000 lines and a warning says so; split a large document into sections if the changed part is further down.
What happens to trailing newlines and Windows line endings?
A single trailing newline is ignored on each side, so text saved with or without a final line break compares equal. Windows CRLF and old-style CR line endings are also treated as normal line breaks, so the same text pasted from different systems compares cleanly.
Are my texts uploaded or stored?
No. Both texts and the diff are processed with JavaScript in this browser tab; nothing is sent to a server, saved or logged. Closing the page clears the input and the result.
Can I compare more than two versions at once?
The tool compares exactly two texts at a time. To check a third version, keep one side fixed and paste the new text into the other side, or compare each version against the one before it.

Background reading

Format guides that explain the trade-offs behind Text Diff.