| Original line | Changed line | Change | Text |
|---|---|---|---|
| 1 | 1 | ToolsFiesta release notes | |
| 2 | − | Version 1.2 | |
| 2 | + | Version 1.3 | |
| 3 | 3 | - Faster page loads | |
| 4 | 4 | - New word counter | |
| 5 | + | - New text compare tool | |
| 5 | 6 | - Bug fixes for the date picker | |
| 6 | − | Thanks for using ToolsFiesta. | |
| 7 | + | Thanks for using ToolsFiesta! |
How to use the Text Compare (Diff)
- 1Paste the earlier version into the Original box.
- 2Paste the newer version into the Changed box.
- 3Press Compare. Tick Ignore whitespace differences if spacing changes should not count.
- 4Read the summary of added, removed and unchanged lines, then scan the highlighted result: green lines marked + were added and red lines marked − were removed.
How the comparison works
The tool compares the two texts line by line. It first finds the longest common subsequence: the largest set of lines that appear in both texts in the same order, even if other lines sit between them. Those lines are shown as unchanged. Every other line in the original is marked as removed, and every other line in the changed version is marked as added.
This is the same idea used by classic diff programs and version control systems. It produces the smallest possible set of additions and removals, so a single inserted line in the middle of a long document shows up as one green line rather than making everything below it look different. The two line-number columns show where each line sits in the original and changed text.
Example
The sample texts are a short set of release notes. The changed version updates the version number from 1.2 to 1.3, adds a line about a new text compare tool, and replaces the full stop at the end of the last line with an exclamation mark. Comparing them gives 3 added lines, 2 removed lines and 4 unchanged lines.
Notice that an edited line appears as a removal followed by an addition. Because the comparison works on whole lines, changing one character marks the whole line as changed. Splitting long paragraphs into shorter lines before comparing makes the result easier to read.
Ignoring whitespace and other tips
With Ignore whitespace differences ticked, runs of spaces and tabs are treated as a single space and spaces at the start and end of lines are ignored. This hides changes in indentation or alignment so you can focus on the words themselves. Leave it off when spacing matters, such as in Python code or YAML files.
For structured data, format both sides the same way first. Running each JSON document through the JSON formatter puts one key on each line, so the diff points to the exact value that changed. For lists, removing repeats with remove duplicate lines and sorting both versions makes it easy to see which items were genuinely added or dropped.
Frequently asked questions
Is my text uploaded anywhere?
No. The comparison runs entirely in your browser, so you can safely compare contracts, private notes or code. Nothing is sent to a server or stored.
How large can the texts be?
Each side can have up to 5,000 lines. That keeps the comparison fast on phones as well as computers. For longer files, compare one section at a time.
Why is a whole line highlighted when I only changed one word?
The tool compares complete lines, so any change inside a line marks the old line as removed and the new one as added. Place the two highlighted lines side by side to spot the exact word.
Does it detect lines that were moved?
A moved line appears as a removal in its old position and an addition in its new one. The tool keeps the largest block of lines that stayed in order and reports everything else as changes.
Can I compare word counts as well as content?
This tool focuses on which lines changed. To compare the length of two versions, paste each into the word counter. You will find more tools for working with text on the text tools page.