What is this tool?
This text diff checker compares two versions of text and shows what was added, removed, and left unchanged. Writers, editors, and developers use it to review document revisions, config changes, or code. Paste or drop a file into Original and Modified and the diff updates as you type. It uses the Myers diff algorithm, so a single inserted line is shown as one change even in long files. Choose Line, Word, or Character precision, and ignore whitespace or case if you like. The Unified and Side by side views show line numbers, colour each change, highlight the changed words inside a line, and collapse long unchanged stretches. Jump between changes with Prev and Next, copy the diff, or download a .patch file. The comparison runs locally in your browser, and nothing is uploaded.
How to Use
- Paste the older text into Original and the newer text into Modified, or drop a file anywhere on either box.
- Pick Line, Word or Character precision. Under Ignore, tick Whitespace or Case if those changes do not matter.
- Choose Unified or Side by side. Long unchanged stretches are collapsed; click Show unchanged lines to expand them.
- Use Prev and Next, or the P and N keys, to jump between changes.
- Click Copy diff, or Download .patch for a unified diff that git apply and patch understand.
Frequently Asked Questions
What do the colours and signs mean?
Red rows marked with a minus sign were removed from the original, and green rows marked with a plus sign were added in the modified text. Inside a changed line, the exact words that changed are highlighted more strongly. The two number columns show each line's position in the original and in the modified text.
How is the similarity percentage calculated?
It is the share of unchanged units out of all units in the diff. A unit is a line, word, or character, depending on the Precision you pick.
Can I ignore spacing or capitalization changes?
Yes. Tick Whitespace to treat runs of spaces and tabs as one space and to ignore leading and trailing space. Tick Case to ignore uppercase and lowercase differences.
What is in the .patch file?
A standard unified diff of the two texts with three lines of context, which git apply and patch can read. It always compares the exact texts, so the Ignore options do not change it.
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