Compare two PDFs
Compare text and page appearance across two versions of a PDF. Use Compare two PDFs locally with practical instructions, output settings and format limits.
Compare two PDFs
Compare two PDF versions page by page using extracted text and rendered pixel differences. Download a ZIP with a JSON report and difference images for changed pages. Use it to investigate edits or layout shifts in short documents, then interpret the results with the source versions rather than treating pixel changes as semantic conclusions.
- Review changes between report versions
- Find shifted page content after re-export
- Inspect text and visual differences in a short PDF
How to use Compare two PDFs
Add the two versions
Upload exactly two PDFs with the earlier version first and the later version second. Each document may contain up to twenty pages for this comparison.
Choose comparison resolution
Set the visual comparison DPI between seventy-two and one hundred twenty. Higher resolution can reveal more fine differences but increases the amount of rendered pixel data.
Create the comparison package
Run Process document to compare corresponding page positions. The output includes extracted-text changes, pixel-difference statistics and PNG difference images when rendered pages differ.
Interpret changes alongside sources
Download and unpack the ZIP, then review comparison.json and the difference PNGs. Check the original versions to distinguish meaningful edits from rendering or layout changes.
Understand the settings
- Visual comparison DPI
- Visual comparison DPI accepts values from 72 to 120, using whole numbers. The initial value is 90. Change it for a specific output requirement, then check the result before processing more files.
A report after a layout revision
Two twelve-page report versions should differ only in a corrected caption. Add the earlier PDF first and compare at ninety DPI. Review the text diff and changed-page PNGs to see whether the export also introduced unexpected page shifts or font changes.
Check your result
Choose a file, adjust the settings, then download the result. Upload exactly two PDFs. ZIP contains textual changes, pixel difference statistics and visual difference PNGs; maximum 20 pages. Open the saved output in the app or workflow where you plan to use it. Check one representative result before repeating the same settings with more files. The original files stay unchanged.
What to know before you start
- Files are processed on this device. Browser memory and engine-specific limits apply. Save results before reloading.
- Upload exactly two PDFs. ZIP contains textual changes, pixel difference statistics and visual difference PNGs; maximum 20 pages.
- Upload up to 20 files, at least 2 with a combined size of at most 100 MB. The completed output must fit within 200 MB.
- Files are checked by the local engine; a matching filename alone is not proof of valid contents.
- Selections and completed jobs stay available while you navigate inside this tab. Use My files to revisit results. Reloading or closing the tab clears the workspace; download results you want to keep first.
Compare two PDFs: common questions
Does comparison automatically align moved pages?
The tool compares pages at corresponding physical positions rather than finding a best match across reordered documents. An inserted cover or moved section can therefore produce differences on many later positions; interpret the report with page order in mind.
Do pixel changes always mean text changed?
No. Font rendering, layout shifts, image changes and page-size differences can alter pixels even when extracted text is identical. The report separates text and visual equality so you can examine both kinds of evidence together.
What happens when page counts differ?
The report records both page counts and compares through the longer document. A missing counterpart is represented in the visual comparison, so added or removed pages can be identified alongside text differences at those positions.
Can this compare a long document?
Comparison is limited to twenty pages per input PDF, with an additional rendered-pixel bound per page. Extract relevant sections first when investigating a larger file, and keep the two selections aligned by corresponding page position.
Does Compare two PDFs upload files to another service?
Processing runs in this browser, on your device. Files and pasted input are not uploaded to a conversion server. The website and required engine assets must load first; large operations depend on available device memory.
Can I continue after changing pages?
Selections and completed jobs stay available while you navigate inside this tab. Use My files to revisit results. Reloading or closing the tab clears the workspace; download results you want to keep first.