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Diff Checker – Compare Two Texts Online

Paste an original and a changed version to see exactly what was added and removed. The comparison runs in your browser, so your text stays on your device.

Compare by

Paste text into both boxes to compare them.

How to compare two texts

  1. Paste the original text into the Original text box and the new version into Changed text. Press Try an example to see how it works.
  2. Choose how to compare: by Lines, Words or Characters.
  3. Set the options if needed: ignore upper/lower case, and in Lines mode ignore spaces. Use the swap button to exchange the two sides.
  4. Read the result under Differences. Additions are green, removals are red, and the summary counts both.

Features

  • Three comparison modes: lines, words and characters.
  • Line numbers for both versions in Lines mode, with + and − markers beside every changed line.
  • Inline highlighting in Words and Characters modes, with removed text struck through.
  • Ignore case in every mode.
  • Ignore spaces in Lines mode, including repeated spaces inside a line, not only at the ends.
  • Swap sides with one tap to reverse the comparison.
  • Added and removed counts, plus a clear message when the texts are identical.
  • Stays responsive: very large or very different inputs are stopped with a message instead of freezing the page.
  • Built on jsdiff, a widely used open-source diff library.

Why use Fileora's diff checker

People compare contracts, essays, configuration files and code, and much of that is confidential. Fileora runs the comparison in your browser, so the text never leaves your device. It's free, needs no account, and the layout stacks the two boxes on a phone so you can check a change on the go.

How to read a diff

Think of the result as a set of instructions for turning the original into the changed version. A red line with a − was in the original and has been removed. A green line with a + is new. Lines without a marker are unchanged and are shown for context.

When a line has been edited rather than added, it appears twice: the old version in red, followed by the new version in green. In Lines mode, the two number columns show where each line sits in the original and in the changed text, which makes it easy to find the same place in your editor.

For prose, Lines mode can be too coarse, because a whole paragraph is often a single line. Switch to Words mode to see exactly which words changed. For short strings such as serial numbers, Characters mode picks out a single swapped letter.

Tips for cleaner comparisons

  • Turn on Ignore spaces when one version was re-indented or reformatted, so only meaningful changes remain.
  • Format both JSON documents the same way with the JSON formatter, ideally with sorted keys, before comparing them.
  • Use the word counter to see how much longer or shorter a new draft is.

Frequently asked questions

How do I compare two texts?

Paste the original into the left box and the changed version into the right box. The differences appear below straight away, with added lines in green marked + and removed lines in red marked −. A summary shows how many were added and removed, or tells you the texts are identical.

What is the difference between comparing by lines, words and characters?

Lines mode treats each line as a unit and is best for code, configuration files and lists; it shows line numbers for both versions. Words mode highlights changed words inside running text, which suits documents and articles. Characters mode shows every single changed letter, which helps with IDs, codes and typos.

Can it ignore spaces and letter case?

Yes. Ignore upper/lower case treats Hello and hello as the same in every mode. In Lines mode you can also switch on Ignore spaces, which ignores spaces at the start and end of a line and also differences in the number of spaces inside it, so a b and a b count as equal.

Is my text uploaded anywhere?

No. The comparison is done by JavaScript running in your browser, using the open-source jsdiff library. Nothing you paste is sent to a server or saved, so it is safe for contracts, private notes and source code.

Why did I get a message that the texts are too large?

Comparing two very long or very different texts can take a lot of work. To keep the page responsive, the tool stops after a few seconds and asks you to compare smaller sections instead, for example one chapter or one file at a time.

Can it merge the two versions?

No. The diff checker shows differences between two texts but does not merge them or compare three versions at once. Use it to review changes, then edit the version you want to keep.

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