Toolivaro

Free Text Diff Checker

Compare two blocks of text line by line with added, removed, and unchanged highlighting plus change statistics — fully local.

Processed locally in your browser

How is the result calculated?

A one-line config change

Comparing a config file before and after a retry-timeout change: the diff shows one removed line (timeout = 30), one added line (timeout = 60), and the surrounding lines unchanged — 2 changed of 8 lines, a 25% change ratio.

Input Value
original host = api.example.com timeout = 30 retries = 3
updated host = api.example.com timeout = 60 retries = 3
Result 1 added · 1 removed · 1 unchanged · 25% changed

What is the formula and its assumptions?

Diff method

diff = longest-common-subsequence(left, right) over lines

Symbol Meaning
left original text, split into lines
right new text, split into lines
LCS the longest sequence of lines present in both inputs in order

Lines outside the LCS are reported as removed (from the left) or added (from the right); the LCS itself is unchanged context.

What are the most common mistakes?

  • Expecting word-level granularity from a line-based diff — lines are atomic here.
  • Comparing texts with different line endings (CRLF vs LF) — they are normalized first, which can mask or reveal changes depending on the source.
  • Forgetting the ignore-whitespace option when reformatting changed indentation everywhere.
  • Uploading proprietary or personal text to an online diff service — this tool is fully local.

What are the assumptions and limitations?

  • The comparison is line-based, not word-based or semantic.
  • Inputs are capped (with an explicit notice) to keep the page responsive.
  • The tool reports textual differences — it cannot judge which version is correct.

Where do the numbers come from?

Last reviewed August 5, 2026 · Version 1.0.0 · Toolivaro does not guarantee external content.

Frequently asked questions

Is this the same algorithm as git diff?

Conceptually yes — git’s default diff also aligns files around a longest common subsequence, with refinements (like Myers’ algorithm) for speed. The result for typical text is the same shape of added, removed, and unchanged lines; this tool documents its method openly and caps inputs for responsiveness.

Why does the diff sometimes show more changes than I expected?

Line-based comparison treats whole lines as atomic. If one line changed in the middle, that line is one removal plus one addition — not a word-level edit. Reformatted code (new wrapping, reindentation) can therefore produce large diffs even though the meaning is unchanged.

Does the tool handle very large files?

Yes, with a documented cap: inputs beyond the line limit are truncated with an explicit notice rather than freezing the tab. For files in the tens of thousands of lines, a purpose-built diff tool is the better choice.

Found a mistake or have a correction? Report it — we review every correction.