Compare PDFs

Find what changed between the lines.

Compare text page by page, or compare rendered pages and download red difference images. Visual comparison detects layout and scanned-page changes at 72 DPI; tiny rendering differences may also appear.

How to use Compare PDFs

1. Open your document from your device.
2. Adjust the settings and preview the result.
3. Read text results on screen or download your file. Your original remains untouched.

Local by design

Your documents are processed on your device. No account, payment or document upload is required.

Enable JavaScript to use the document workspace.

Compare PDF versions without overlooking the context

A revised document can look almost identical to its predecessor while changing a date, a payment term or an important exception. PDF comparison helps you locate differences before you decide what they mean. It is useful for reviewing revised proposals, checking corrected reports and comparing an exported document with an earlier delivery. Keep both originals and give them recognisable filenames so that the direction of the comparison is clear.

SandboxPDF compares documents locally. The browser needs access to both files, but it does not upload their contents to a document-processing server. Comparison is an inspection aid, not an approval decision. A highlighted difference does not tell you whether the change is correct, authorised or significant. Read the surrounding paragraph and inspect the source page before accepting an important revision.

Choose the comparison that matches your document

Text differences and visual differences answer different questions. Text comparison can reveal altered wording, but extraction may put columns, headers and footnotes in an unexpected order. Visual comparison can reveal a changed chart or moved signature, but harmless changes in fonts, compression or rendering may also create visible differences. A scanned page needs particular care because its words may exist only as pixels.

Page alignment matters as much as the comparison method. If someone inserts a cover page, comparing the first page of each file may pair unrelated content. Inspect page counts and identify corresponding sections before interpreting a long list of changes. Where possible, compare matching excerpts created from copies of the two originals. Do not delete pages from your only source documents just to make their lengths agree.

A reliable review sequence

1. Open the earlier PDF and add the revised version in the order shown by the workspace. Confirm that both filenames match the versions you intended to review.
2. Select the available comparison settings and create the result. Give large files time to render; running several heavy tools simultaneously can compete for browser memory.
3. Inspect the reported changes against both source pages. Check dates, amounts, units, names, page references and phrases such as “unless” or “except.”
4. Review pages containing tables, diagrams, signatures or scans visually, even when the extracted text appears unchanged.
5. Download the comparison output if you need a review record. Reopen it and keep the two source versions alongside it so another reviewer can understand the evidence.

Avoid false confidence

Two files with the same text are not necessarily equivalent. A changed hyperlink, annotation, permission setting or digital signature may matter even if the visible sentences do not change. Conversely, a re-export can reorder internal text objects without changing the intended reading order. Treat these as separate checks rather than expecting one difference score to settle every question.

For contracts and regulated documents, use a documented review process. Record the source versions, investigate each material change and have the responsible person approve the final document. SandboxPDF does not establish authenticity or replace legal review. For a practical example of separating wording changes from layout noise, read how to compare PDF versions.

Frequently asked questions

Does comparison edit either original?

No. Processing creates a separate result. Keep the originals so you can investigate differences and repeat the comparison with other settings.

Why do identical-looking pages show differences?

Fonts, image compression, page positioning and extraction order can change during export. Inspect the actual words and page images before treating every difference as a substantive revision.

Can it compare scanned documents?

Scans require visual inspection. If you need text-based analysis, create and check searchable copies with OCR first; recognition errors can otherwise look like revisions.

Does an unchanged result prove two contracts are equivalent?

No. A comparison cannot establish legal equivalence, authorisation or certificate validity. Review signatures, attachments and other relevant properties separately.

What should I do if one version has extra pages?

Identify which sections correspond before interpreting the output. Compare matching excerpts if necessary, while preserving both complete original documents.