About
Justools

Free, private browser tools for everyday tasks.

PDF tools

  • Merge PDF
  • Split PDF
  • Organize PDF
  • Rotate PDF
  • Delete PDF Pages
  • Add Page Numbers
  • Watermark PDF
  • Image to PDF
  • PDF to JPG
  • PDF to PNG
  • Remove PDF Password
  • Compress PDF
  • Protect PDF
  • PDF to Text
  • Crop PDF
  • Flatten PDF

Image tools

  • Image Converter
  • JPG to PNG
  • PNG to JPG
  • JPG to WebP
  • WebP to JPG
  • WebP to PNG
  • Image to WebP
  • Image Cropper
  • Lasso Crop
  • Remove Photo Metadata
  • SVG Optimizer
  • Resize Image
  • Compress Image
  • Remove Background
  • Image to Text

Developer tools

  • JSON Formatter
  • CSV to JSON
  • Hash Generator
  • Base64
  • URL Encode
  • Timestamp Converter
  • Diff Text
  • Case Converter
  • Word Counter
  • Color Contrast
  • Unit Converter

Utility tools

  • QR Code Generator
  • Trim Video
  • Merge Video
  • Screen Recorder
  • Voice Recorder

Creative tools

  • Coloring Pages
  • Graph Paper Generator
  • Spin the Wheel

Calculators

  • Cost of Raising a Child Calculator
  • Calorie Deficit Calculator
  • BMI Calculator
  • Age Calculator
  • Date Calculator
  • City Time Converter
  • Scientific Calculator
  • Fraction Calculator
  • Cost of Living (20 countries)
  • Budget Planner
  • Pay Raise Calculator

Company & legal

  • All personal tools
  • Insights
  • Business
  • Learn
  • About
  • Help
  • Support
  • Contact
  • Privacy
  • Terms of Use
  • Disclaimer

© 2026 Justools. General information only, not financial advice.

Diff Text

Compare two text blocks line by line to see what was added, removed, or left the same.

Paste text on both sides to compare lines.

Other useful tools

Free tools that often go together. Everything runs in your browser.

  • Developer toolsCase ConverterConvert text casing
  • Developer toolsWord CounterCount words and characters
  • Developer toolsJSON FormatterFormat and validate JSON
  • Developer toolsCSV to JSONConvert CSV and JSON both ways
  • Developer toolsHash GeneratorSHA-256 and other hashes
  • Developer toolsBase64Encode and decode Base64

How to use this tool

  1. Paste original text on the left.
  2. Paste changed text on the right.
  3. Review added and removed lines in the diff.

Frequently asked questions

What kind of diff is this?▾

This is a line-based diff: it compares two blocks of text line by line using a longest common subsequence algorithm and highlights which lines were added, removed, or unchanged. It works well for comparing whole lines, such as config files, log entries, or short drafts, but it does not highlight individual word changes within a line the way some code editors do.

Who uses a text diff tool?▾

Writers comparing two drafts of an email or document, developers checking what changed between two versions of a config file, and anyone reviewing a before and after copy of notes, quotes, or pasted text to spot what was edited.

When is it useful?▾

Common cases include comparing two drafts of the same email, checking a config file before and after a change, reviewing edits a colleague made to shared notes, or spotting what changed between two versions of a pasted API response.

Does it compare words inside a line?▾

No. This version compares full lines only, so a single changed word marks the entire line as different rather than highlighting just that word.

Can it handle large files?▾

Very large pasted text may slow the tab, since the whole diff table is held in memory. Split large files into smaller sections if the comparison feels sluggish.

Is my text private?▾

Yes. Both text boxes are compared entirely in your browser and are never uploaded.

Does it save history?▾

No. The tool does not store previous diffs, so refreshing the page or leaving the tab clears both text boxes.

Processed locally in your browser. Your files are never uploaded to our servers.