How to Compare Two Texts and See Exactly What Changed
2026-07-27
Finding what changed between two versions of a document by reading both is slow and unreliable. The eye skips over exactly the small edits that matter — a changed number, a flipped negation, a deleted clause in a contract.
Step by step
- Open Text Compare.
- Paste the original into the first box and the new version into the second.
- Read the result:
-for removed lines,+for added, a space for unchanged. - Download the diff if you need to share it.
How the comparison works
The tool finds the longest common subsequence of lines between the two texts — the same approach version control uses. That matters more than it sounds. A naive line-by-line comparison marks everything after an inserted paragraph as changed, because line 12 in one version is now line 13 in the other. Finding the common subsequence first means an inserted paragraph shows up as one addition and nothing else moves.
Ignoring the noise
Text that has been re-wrapped, re-indented or pasted through a different editor often differs in whitespace on nearly every line while saying exactly the same thing. Two switches handle this:
- Ignore spacing — collapses runs of whitespace and trims line ends, so reflowed text compares on content alone.
- Ignore letter case — useful when comparing text that has been through a style pass.
What it is good for
- Checking which clauses changed between two contract drafts.
- Seeing what an editor actually altered in your copy.
- Comparing two config files that are behaving differently.
- Verifying that a find-and-replace did only what you intended.
Both versions are compared in your browser, so contracts, drafts and source code never leave your device.