Text Compare

The tool splits both texts into lines and computes the longest common subsequence (LCS) to find which lines are shared between the two versions. Lines in the original that do not appear in the new text are shown as removed (red). Lines in the new text that do not appear in the original are shown as added (green). Lines present in both versions are shown as unchanged.

The similarity percentage shows how much of the text is shared between the two versions. A 100% similarity means the texts are identical. A 0% similarity means no lines are shared. For example, if 9 out of 10 lines are unchanged, the similarity is 90%.

Yes. The comparison is case-sensitive by default. "Hello" and "hello" are treated as different lines. This matches the behaviour of standard diff tools, which are designed for precise text comparison.

A + symbol marks a line that was added in the new text (present in "New Text" but not in "Original"). A - symbol marks a line that was removed (present in "Original" but not in "New Text"). A space marks a line that is unchanged in both texts.

This tool compares exactly two texts at a time. To compare a series of revisions, compare versions one pair at a time: original vs. revision 1, then revision 1 vs. revision 2, and so on.

Text Compare is read-only: it shows you what is different between two texts without changing them. Find and Replace is a writing tool: it modifies the text by substituting one pattern with another. Use Text Compare for proofreading, auditing changes, and spotting differences. Use Find and Replace to apply corrections.

It matches identical lines between the two versions and flags everything else as added or removed. Each line is compared as a whole string, so two lines match only when they are identical character for character. Matched lines act as anchors, and any line without a partner on the other side becomes a difference. For example, editing one word in the line "The report is due Friday" flags the whole line, not just that word.

A line-level diff treats each full line as the unit of comparison, while a character-level diff pinpoints the exact characters that changed inside a line. This tool works at the line level: change one word in a ten-word sentence and the entire line shows as removed and added. A character-level view would underline only that word. Line-level output is faster to scan when reviewing documents, contracts, or configuration files.

Because lines only match when they are identical character for character, an invisible trailing space makes two otherwise equal lines different. "Hello world" and "Hello world " are distinct strings, so the diff marks one as removed and the other as added even though they look the same on screen. To remove this noise, run both texts through a whitespace normalizer first, then compare the cleaned versions.

Because the diff matches lines in order, a moved paragraph reads as a deletion at its old position and an insertion at its new one, even when not a single word changed. Shared lines are kept in sequence, so the tool cannot recognize the same block appearing earlier or later in the other text. For example, swapping two sections of a document can cut the similarity score in half. When order does not matter, sort both texts first or compare the sections separately.

No. The entire comparison runs in your browser using JavaScript. No text is uploaded to any server. Your content stays completely private.