Text Compare

How to compare two texts

1. 1

   Add two texts

   Type, paste or import a .txt file into Original and into Modified.

2. 2

   Choose options

   Optionally ignore case or leading and trailing whitespace on each line.

3. 3

   Compare

   Press Compare, then read the result side by side or in a single column. Copy it or download a report.

Adding text

There are two plain-text editors, Original and Modified. You can type in them, paste, or import a local UTF-8 .txt file, up to the size limit below.

• Paste button. The Paste button reads the clipboard only when you press it. The browser may ask for permission. If it is blocked, click in the editor and press Ctrl+V (Cmd+V on a Mac) instead.
• Clear, Swap, Example and Reset. Each editor has Clear. Swap exchanges the two texts. Load example fills both with made-up sample text. Reset clears everything.
• Comparing. Press Compare, or press Ctrl+Enter (Cmd+Enter on a Mac) in an editor. Nothing is compared on every keystroke. After you edit a text or change an option, the result is marked out of date until you press Compare again.

How the comparison works

The texts are compared line by line. Within changed lines, the changed words are highlighted.

• Pairing changed lines. Changed lines are paired in order within each changed block, so the first removed line is shown against the first added line, and so on.
• When words are not highlighted. Word highlights are skipped, and the whole line is marked instead, for lines longer than 2,000 characters or when the paired lines share little text.
• Blank lines. Blank lines are kept and compared like any other line. Text is never trimmed or reflowed.

Options

• Ignore case. Lines that differ only in upper and lower case count as matching.
• Ignore leading and trailing whitespace. Applies to each line separately. Spaces inside a line still count. With this option, a missing line break at the very end of a text is also not counted as a difference.
• Your text is shown as written. Options only affect which lines match. The results always show your original text. A line that matches only because of an option is marked with ≈, which means it differs only in ignored case or whitespace.

Line endings

Windows (CRLF), macOS and Linux (LF) and old Mac (CR) line breaks are all treated as the same line break, so a file saved on another system does not show every line as changed. The result notes when the two texts use different line endings.

A missing line break at the end of one text is shown as a separate note in the results.

Reading the results

• Views. Choose side by side or unified. Phones start in unified. Line numbers from both texts are shown.
• Additions and removals. Added lines are shown with + and green. Removed lines are shown with − and red. The marker means the result does not rely on colour.
• Long lines. Long lines wrap by default. Turn off the Wrap long lines switch to scroll horizontally instead.
• Unchanged lines. Long runs of unchanged lines are collapsed to 3 lines around each change. A button shows them.
• Summary. The summary gives the number of lines added and removed. When nothing differs under the selected options, it says the texts are identical.
• Markup is shown as text. Text such as <script> or HTML tags is displayed as literal text. It is never run or rendered.

Copy and download

Copy report and Copy changes copy plain text. Download report saves a .txt comparison report with + and − markers, line numbers and the active settings.

It is a readable report, not a patch file for patch tools.

Limits

per text

2 MB

lines per text

50,000

time limit for matching

4 s

result rows shown on the page

3,000

The size and line limits apply to each text separately. Matching has a time limit of 4 seconds. For very different large texts that reach it, the shared start and end are kept and everything between is shown as one replaced block, with a notice. The page shows up to 3,000 result rows; the downloaded report always contains the full comparison.

Frequently asked questions