PDF Compare

About PDF Compare

This tool compares two PDF files and shows their differences. It compares file properties, metadata, page count, and file size. All processing happens in your browser for complete privacy.

What does the tool compare?

The tool compares file name, file size, number of pages, PDF version, and metadata (title, author, etc.).

Can it compare content?

This tool compares file-level properties and metadata. For detailed content comparison, you would need specialized diff tools.

What is the file size limit?

Each PDF file must be under 50MB.

Is my data safe?

Yes! All comparison happens in your browser. Your files are never uploaded to any server.

Can this tool detect text changes between two PDF versions?

This tool compares file-level properties (size, page count, metadata, PDF version) which catches major structural differences. For word-by-word text diffs, use Adobe Acrobat's Compare Files feature, Draftable.com, or pdftotext + git diff in the terminal — those approaches do semantic content comparison.

Why does the size differ even if the document looks identical?

PDF size depends on: image compression level (JPEG vs Flate), embedded fonts (subset vs full), object streams enabled, linearization (web-optimized), encryption, redaction marks, change tracking. Two visually identical PDFs can differ by 5x in size based on these settings. Use a tool like Smallpdf to compress before comparing.

What metadata fields are compared between the two files?

Title, Author, Subject, Keywords, Creator (the app that authored content), Producer (the library that wrote the PDF), CreationDate, ModDate, and PDF Version (1.4, 1.7, 2.0). Differences in Producer often reveal which library generated each PDF (LaTeX, Word, Chrome, Acrobat).

Is the maximum 50MB per file a hard limit?

It is a soft browser-memory limit to prevent tab crashes. PDF.js loads the entire file into RAM. Modern laptops handle up to 200MB; mobile phones struggle above 30MB. For huge PDFs, split with pdftk or use a desktop tool like PDF24 Creator or qpdf for comparison.