Text Diff Tool
Compare two blocks of text line by line and highlight differences. Perfect for comparing code, documents, or any text content.
Text Comparison
Legend
About Text Diff Tool
A text diff tool is a comparison utility that analyzes two blocks of text and highlights the differences between them in a clear, visual format. This tool takes two text inputs and lists the differences line by line with color-coded additions and deletions (a changed line appears as a removed line plus an added line), making it easy to identify changes in documents, code, or any text content.
Why use a Text Diff Tool?
Using a text diff tool saves time when reviewing changes, ensures accuracy in document comparisons, and prevents errors when merging content from different sources. It provides visual clarity for complex changes, helps maintain version control, and improves collaboration by making differences immediately apparent to all team members.
Who is it for?
This tool is essential for developers comparing code versions and reviewing pull requests, writers tracking document revisions, editors comparing different drafts, content managers reviewing website changes, legal professionals comparing contract versions, and anyone who needs to identify precise differences between two text documents.
How to use the tool
Paste the original text into the left input field
Paste the modified or comparison text into the right input field
The comparison updates shortly after you stop typing; click Compare Text to run it immediately
Review the highlighted changes showing added and removed lines; tick 'Ignore whitespace' or 'Ignore case' if needed
Copy the diff or download it as a text file
Frequently Asked Questions
How do I compare two pieces of text?
Paste the original text into the left box and the changed text into the right box. The diff appears shortly after you stop typing (or click Compare Text) as a single list of lines: additions (green, +), deletions (red, -) and unchanged lines, each with its line number from the left and right text. The comparison is line by line only — there is no character-level mode and no side-by-side or synchronized-scrolling view. Options: ignore whitespace (leading and trailing spaces on each line) and ignore case. Copy or download the result. Runs entirely in your browser — your text never leaves the device. Useful for: comparing document versions, reviewing edits, finding changes between code versions, log file analysis.
What does the diff highlight?
Two categories of change, plus unchanged lines. **Additions** (green): lines present in the right text but not the left — newly added. **Deletions** (red): lines present in the left but not the right — removed. **Unchanged** (default styling): lines identical in both. A line that was edited shows as one deleted line followed by one added line. The diff is a minimal line diff: it aligns the inputs to maximize matched lines and highlights the actual changes. For very different inputs, the diff may show everything as deleted + everything as added (no shared lines to align).
Is my text sent to a server?
No — diff comparison runs entirely in your browser via JavaScript. Your text never reaches a server, never gets logged. Verify in DevTools' Network tab: comparing makes no HTTP requests. Safe for comparing sensitive document versions (contracts, legal text, internal memos).
What's the difference between line and character diff, and which does this tool use?
This tool only does a line diff: comparison happens line by line, and a line is treated as changed if any character within it differs (it shows as a removed line plus an added line). That suits code and other line-oriented text. There is no character-level or word-level mode, so for prose edits inside a long paragraph you will see the whole line replaced. Tip: put each sentence on its own line before pasting to get finer-grained results.
Does this work for code, JSON, or natural language?
Yes — text diff works on any text content. For code: use it to compare two versions of a function, file, or commit. For JSON: it shows added/removed keys (though [JSON Diff](/tools/json-diff/) is more structure-aware). For natural language: shows edits between draft and revised versions. For structured data where order doesn't matter (object keys), use a format-specific diff tool. For pure text where order matters (most cases), this tool works well.
How is this different from JSON Diff?
[JSON Diff](/tools/json-diff/) is JSON-aware: it understands that JSON objects are unordered ({a:1, b:2} ≡ {b:2, a:1}), arrays are ordered, and structure matters. Text Diff treats everything as plain text — '{a:1, b:2}' and '{b:2, a:1}' show as different by text diff (the byte sequences differ). For JSON comparison, use JSON Diff. For non-JSON text, code, or general comparison, use this Text Diff tool.
How large can the texts be?
Browser performance is the limit. The diff only runs after a short pause in typing, and is fast for typical inputs: comparing a few thousand lines takes well under a second. Very large texts (tens of thousands of lines with many differences) can take noticeably longer and make the page sluggish. For very large texts (log files, full codebases), use command-line tools such as `diff` or `git diff`. This tool fits the common case of comparing emails, documents, code snippets up to a few thousand lines.
When should I use Text Diff vs Text Diff Compare Tool?
Both tools compare text. [Text Diff](/tools/text-diff/) (this tool) shows a line diff with options to ignore whitespace and case. [Text Diff Compare Tool](/tools/text-diff-compare-tool/) is a separate tool with its own interface; try both and pick the output you prefer. For JSON-specific comparison, use [JSON Diff](/tools/json-diff/) instead — structure-aware comparison gives better results.
Share This Tool
Found this tool helpful? Share it with others who might benefit from it!
💡 Help others discover useful tools! Sharing helps us keep these tools free and accessible to everyone.