Private inspect tool
PDF Page Size Checker
Catch mixed or incorrect PDF page sizes before production. Processing stays in your browser.
Check the result yourself
Find the mixed-size and cropped pages
The sample contains A4, US Letter, and a rotated Letter page with a smaller CropBox. Expect three pages and two MediaBox sizes.
Read the steps, expected results and limitations →More file tasks
Use a practical PDF preflight checklist covering page size, bleed, fonts, images, color, page order and final proofing.
How it works
A useful result,
without the upload.
Inspect PDF MediaBox and CropBox dimensions, page count and rotation locally. Identify mixed sizes and download an all-page geometry report before printing. The file is decoded and processed inside this browser tab, so File Preflight never receives its contents.
Worked example
A 612 × 792 point page is US Letter at 8.5 × 11 inches.
How to use the PDF Page Size Checker
- Choose a PDF file using the file picker or sample button.
- Wait for the inspection to complete and view the page count and size groups.
- Review the geometry table showing MediaBox and CropBox dimensions for each page.
- Check for mixed page sizes that may require re-exporting source files.
- Download the all-page report for detailed measurements and documentation.
What happens under the hood
This tool uses pdf-lib to parse the PDF structure locally in your browser. It measures MediaBox and CropBox dimensions for each page, applying UserUnit scaling to convert points to inches. The inspection runs entirely on your device without uploading the file, using pdf-lib's page measurement functions to extract geometric properties without rendering page content.
Before you send the file
- The file is parsed in the browser and is not uploaded.
- This measures MediaBox and CropBox only, not TrimBox, BleedBox, embedded-image resolution, fonts or color mode.
- Mixed page sizes may be intentional; confirm the production specification.
Frequently asked questions
What is the difference between MediaBox and CropBox?
MediaBox defines the physical page boundary, while CropBox defines the visible area. A smaller CropBox can create margins or hide content without changing the MediaBox dimensions.
Can this check for PDF/X compliance?
No. This tool measures page geometry only and does not validate PDF/X compliance, color profiles, fonts, or embedded image resolution.
Why are page sizes grouped at 0.01 inch precision?
Grouping at 0.01 inch precision helps identify truly different sizes while ignoring minor rounding differences in PDF generation.
Does rotation affect the measured dimensions?
No. Rotation does not change MediaBox or CropBox dimensions; it only affects how the page is displayed.
Keep an untouched original and inspect the downloaded file before replacing any production asset. Closing this tab removes the selected files from the tool.