A revision can read smoothly while losing an instruction the reader still needs. Before publishing, compare the revised plain-text draft with the original and review what disappeared as carefully as what was added. The Text Compare tool shows those differences line by line.
This check works well for an article section, a newsletter notice or a short help page. Keep an untouched copy of the original, then paste the version you intend to publish into the second box. The comparison identifies text changes; you still decide whether each change is correct.
Prepare two drafts with comparable line breaks
Copy the same section from each version, including its heading and any closing instruction. Comparing a complete old article against only the new introduction would produce removals that are simply outside the selected section.
Use consistent paragraph boundaries where possible. The tool compares actual line breaks in the pasted text. If one version puts a sentence on one line and the other splits it across two lines, the output can show one removed line and two added lines even though the words are the same. Visual wrapping caused by the width of the text box is different from a pasted line break.
For text copied from a PDF or email with unwanted hard returns, the guide to removing line breaks while keeping paragraphs can help prepare a working copy. Keep the original available and apply the same preparation to both versions before comparing.
Try an example that contains an accidental omission
The following fictional notice has four lines in each version. The revised draft changes the opening time, adds an entry detail and drops an instruction about labelling seeds.
Original text
Autumn seed swap Bring labelled seeds in sealed envelopes. Doors open at 10:00. Please include the variety and harvest year.
Changed text
Autumn seed swap Bring labelled seeds in sealed envelopes. Doors open at 11:00. Entry is free.
- Open Text Compare and paste the first sample into Original text.
- Paste the revised sample into Changed text. Do not include the headings “Original text” and “Changed text” from this guide.
- Leave Ignore case unchecked, keep Ignore leading and trailing whitespace checked, and leave Hide unchanged lines unchecked.
- Press Compare Texts. Press it again whenever you change the text or the options.
With those settings, the result is 2 Lines added, 2 Lines removed and 2 Lines unchanged. The complete diff reads:
Autumn seed swap Bring labelled seeds in sealed envelopes. - Doors open at 10:00. - Please include the variety and harvest year. + Doors open at 11:00. + Entry is free.
The minus prefix identifies a removed line; the plus prefix identifies an added line. Unchanged lines have two leading spaces. The time change appears as one removal and one addition because the tool compares whole lines. It does not highlight just 10:00 and 11:00.
The equal added and removed counts do not mean the revision preserved every instruction. The variety-and-year sentence has no replacement in the new notice. If participants still need that instruction, restore it in the draft before publishing.
Read removed lines before accepting the revision
For each removed line, find its intended replacement or its new position. Mark it as an approved deletion only after you understand why it vanished. Give particular attention to dates, quantities, exceptions, steps and words such as “only” or “unless”; a short deletion can change what a reader does.
Then read the added lines in their surrounding paragraph. In the sample, confirm the new opening time and the statement about free entry against the notice’s source information. A highlighted addition shows that the wording changed, not that its claim is accurate.
If a paragraph was moved, it may appear as a removal and an addition. The tool matches lines that remain in the same order, so it does not label a moved block separately. Check both locations before restoring a line that is already present elsewhere.
Use the ignore options deliberately
Keep case visible when capitalization matters
Ignore case can reduce noise during a review of wording. Leave it unchecked when you need to check names, acronyms or headings. With both ignore options enabled, Entry is FREE. and Entry is free. count as one unchanged line, and the tool reports that the texts are identical under the current comparison options.
That message depends on your settings. For a final check of capitalization and spacing at the ends of lines, uncheck both ignore options and compare again.
Ignoring whitespace only affects the ends of each line
Ignore leading and trailing whitespace is checked by default. It ignores spaces and tabs at the edges of a line when matching. MDN’s JavaScript whitespace reference explains that the whitespace character class covers whitespace characters, which helps explain why this setting handles more than ordinary spaces.
It does not collapse spaces inside a sentence. Comparing Bring labelled seeds. with Bring labelled seeds., which has two spaces after “Bring,” still produces one removed line and one added line with the default settings.
Investigate differences that look identical
An accented letter can have more than one underlying Unicode representation. MDN’s Unicode normalization explanation shows why visually equivalent text can fail a direct string comparison. This tool does not normalize those representations: a test using a single-character é in Café and an e followed by a combining accent produced one removal and one addition.
If two highlighted lines look the same, inspect the original pasted text before deciding it is a wording change. The ignore options do not resolve every invisible character difference.
Use the diff as a review record
Check Hide unchanged lines and press Compare Texts to focus the displayed result on changes. The summary still counts unchanged lines. Copy Diff copies the complete result, including unchanged lines, even when they are hidden on screen.
Matched lines use the original version’s text in the diff. When ignore options are active, that can preserve the original capitalization or edge spaces in the copied result. Copy the final publishing text from your revised draft, rather than treating the diff as a clean replacement document.
Each side is limited to 2,000 lines. For a longer draft, compare corresponding sections and keep a record of which sections you have checked. A final newline can also create a blank line in the comparison.
After resolving omissions, make your edits in the draft and compare it again against the saved original. If a deliberate terminology change needs to be applied across the text, use the whole-word find-and-replace guide, then review the resulting diff. Finish by reading the complete revised page in your publishing preview so you can check its flow, links and formatting alongside the text changes.