See exactly what changed between two blocks of text.
Paste two versions to compare them.
Both versions stay in this tab and are never uploaded.
Paste two versions of something and see exactly what changed — added lines, removed lines, and the unchanged ones around them for context.
The comparison finds the longest common subsequence rather than walking both texts line by line. That distinction is what makes the result readable: a naive comparison marks every line after an insertion as changed, which is technically true and completely useless. Here, inserting a paragraph shows one insertion.
Whitespace and capitalisation can be ignored for the comparison while the text you see stays exactly as you pasted it — so re-indented code or a re-wrapped paragraph does not drown the real changes.
A contract that came back from review, or a page of copy someone edited without tracking changes. This finds what moved.
Comparing the file from a working environment with the broken one usually finds the problem faster than reading either.
Formatters, translators and generators all rewrite text. Diffing before and after shows whether anything unintended came along.
Two pages that were once the same tend to drift. Seeing the difference is the first step to deciding which to keep.
The original on the left, the changed one on the right. The comparison runs as you type.
Added lines are marked with a plus and removed ones with a minus, with line numbers from each side and the unchanged lines kept for context.
Turn off whitespace or case sensitivity when re-indentation or capitalisation would otherwise bury the changes that matter.
One button exchanges the two sides, which turns additions into removals and usually makes more sense of the result.
Line by line. That suits documents, configuration and code, where a line is the natural unit. A line with a single word changed shows as one removal and one addition.
Re-indenting a file or re-wrapping a paragraph changes almost every line without changing anything meaningful. Ignoring it for the comparison leaves only the real edits — and the text shown is still exactly what you pasted.
The work grows with the two lengths multiplied together, so very large pairs are refused rather than left to hang the page. Comparing a section at a time is the way around it, and is usually easier to read anyway.
Open them and paste the contents. Text is what this compares; for PDFs, pull the text out first.
No. Both versions stay in this browser tab, which matters given how often the thing being compared is a contract or an unreleased draft.