How to Compare Two Texts and Find the Differences

Someone sends back "a few small edits" to your document. A contract comes back for signature with "minor changes". A config file stopped working after an update. Reading both versions side by side and hoping to spot the difference is slow and unreliable — a diff checker shows every change instantly.

A woman reviewing a script marked with red pen

What a diff checker does

It compares an original text with a changed one and highlights:

Added text in green.
Removed text in red.
Everything unchanged in plain text.

You see exactly what changed, including a single missing comma or a swapped number.

How to compare two texts

Open the free Text Diff Checker.
Paste the original on the left and the changed version on the right.
Choose how to compare — by line, word or character.
Read the result. A summary shows how many lines, words or characters were added and removed.

The comparison updates as you type and runs entirely in your browser, so confidential contracts and code are never uploaded. Use Swap if you pasted them the wrong way round.

A person comparing data on printed papers

Choosing a comparison mode

Line by line — for code, config files, lists and spreadsheets pasted as text. Each line is numbered in both versions.
Word by word — for articles, essays, contracts and emails. Rewritten phrases stand out without flagging whole paragraphs.
Character by character — for typos, IDs, codes and URLs where one character matters.

Useful options

Ignore whitespace changes (line mode) treats lines that differ only in spaces or tabs as the same — handy when code was re-indented.
Ignore case (word and character modes) skips differences like "Price" vs "price".

Real-world uses

Contracts and policies: catch quiet changes to amounts, dates or obligations before signing.
Editing: see what an editor or AI tool actually changed in your draft.
Code and config: spot the line that broke something.
Lists: compare two exports to see which entries were added or dropped. Tidy them first with Remove Duplicate Lines.

FAQ

Is there a size limit? No fixed limit, but very long and very different texts may take too long to compare. If that happens, compare a smaller section.

Can I compare JSON? Yes. Format both versions with the JSON Formatter first so the line-by-line view lines up.

Is my text stored anywhere? No. Nothing you paste leaves your device.

Try it now

Find every change with the free Text Diff Checker.