Revised contracts, estimates, drawings, and reports do not always come with a clear list of changes. Manual page-by-page review can miss inserted pages or small text edits.
A practical workflow is to align corresponding pages first, then inspect both visual and text differences. Browser Kitty's PDF Compare performs that workflow in the browser.
What to check before comparing PDFs
When pages are inserted or removed, comparing page 1 to page 1, page 2 to page 2, and so on can produce many false differences.
A better workflow is to align corresponding pages first, then inspect the visual and text changes.
- Whether pages were inserted or removed
- Whether page order changed
- Whether the PDF is scanned or contains selectable text
Do not rely on only one comparison view
A highlighted diff is useful, but small rendering shifts can also appear as changes. Side-by-side, overlay, slider, and blink views help you judge whether the content actually changed.
- Diff: find likely changes quickly
- Side-by-side: read both versions carefully
- Overlay or blink: inspect alignment and shape changes
Scanned PDFs may not have text differences
Scanned PDFs often store text only as pixels. In that case, text comparison is unavailable and you mainly rely on visual differences. PDFs with real text can provide both visual and text comparison.
When comparing sensitive PDFs
For contracts and internal documents, confirm whether uploading the file to a comparison service is acceptable. A local browser-based tool can perform the comparison without sending the PDF itself to a backend.
Step by step
- Select the before and after PDFs.
- Wait for page alignment, then check for inserted or removed pages.
- Start with the diff view, then switch to side-by-side, overlay, slider, or blink when needed.
- For PDFs with real text, review the text differences too.
- If minor rendering noise dominates, adjust sensitivity or the small-difference filter.
PDF Compare
Compare two PDFs locally to find added or removed pages plus visual and text changes.
Tips and limitations
- For contracts or drawings, verify important findings against the original PDFs.
- High-quality rendering uses more memory, so start with standard quality for large files.
- Treat automated differences as an aid for review, not as a complete replacement for checking important documents.
Frequently asked questions
Can password-protected PDFs be compared?
PDF Compare supports password-protected PDFs. Enter the required password to open the file before comparing it.
Does it work with scanned PDFs?
Yes. If the text exists only as pixels, text differences are unavailable, so the comparison mainly relies on visual changes.
Are the PDFs uploaded to a Browser Kitty server?
PDFs selected in PDF Compare are processed in the browser and are not uploaded to a Browser Kitty backend.