PDF Preflight Checker

Verify image resolution (DPI), bleed margins, and color mode for every page — instantly in your browser. No upload, no account, completely free.

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Drop your PDF here

or click to choose a file — processed locally, never sent to a server

Analysing…

Per-page report

PASS meets threshold FAIL below threshold WARN no bleed box declared N/A no embedded images
Page Size (pts) Images / DPI DPI check Color mode Bleed

How it works

The checker loads your PDF entirely in the browser using pdf.js, then inspects each page's internal data structures — no file ever leaves your computer.

1 · Load pdf.js decodes the PDF binary client-side. Pages are iterated one by one.
2 · Image DPI Each embedded image XObject reports its pixel dimensions. DPI = pixels ÷ (display size in inches). Display size comes from the image's transformation matrix relative to the page, which is measured in PDF points (1 pt = 1/72 in).
3 · Color mode XObject resources carry a ColorSpace entry: DeviceCMYK, DeviceRGB, or DeviceGray. Mixed pages are flagged when different color spaces appear on the same page.
4 · Bleed Standard print bleed is 3 mm (≈ 8.5 pt) or 0.125 in (9 pt) on every side. The checker compares the PDF's BleedBox against the TrimBox or MediaBox. Missing BleedBox = warning; bleed below standard = fail.

DPI formula: DPI = image_pixel_width ÷ (display_pts ÷ 72). Example: a 600 px wide image displayed across 144 pt (2 in) → 600 ÷ 2 = 300 DPI.
Bleed formula: 3 mm × (72 ÷ 25.4) = 8.504 pt per side.

Frequently asked questions

What DPI do I need for print?
Professional offset and digital printing almost universally requires 300 DPI at final print size for photographic images. Line art and text-only elements can be lower because they are rendered as vectors, not rasterised images. If you export your artwork at 100% scale with 300 DPI, images embedded in the PDF should meet this threshold. Anything below 200 DPI will look noticeably soft in print; below 150 DPI it will look pixelated.
What is bleed and why does it matter?
Bleed is a strip of artwork that extends beyond the finished trim edge of a printed piece. Because cutting machines have a small tolerance (typically ±1–2 mm), printing without bleed risks leaving a thin white strip along the edge of your final piece. The industry standard is 3 mm on every side in Europe and most international markets, or 0.125 in (⅛ in) in the US. In PDF terms this means your BleedBox must be at least 3 mm larger than your TrimBox on each side. This checker detects whether a BleedBox is present and whether it meets the minimum margin.
My PDF shows WARN for bleed — what should I do?
A WARN means the PDF contains no BleedBox entry at all. Some printers accept this if your artwork visually extends to the edge of the MediaBox. To be safe, re-export from your design application with bleed enabled: in InDesign use "Marks and Bleeds → Use Document Bleed Settings"; in Illustrator set a 3 mm bleed in Document Setup before exporting; in Affinity Publisher set the bleed in Document Setup and check "Include Bleed" on PDF export.
Why does this tool report color mode as RGB when I set CMYK in my file?
PDFs can contain a mix of color spaces. A CMYK document may still embed RGB photographs (common when placing JPEGs from a camera directly into InDesign without converting them). Each embedded image carries its own ColorSpace. This tool reports the color spaces it actually finds in XObject image resources. If you need fully CMYK output, convert all placed images to CMYK before embedding, or use your application's "Convert to CMYK on export" option.
Is my PDF uploaded to a server?
No. The entire check runs inside your browser using the open-source pdf.js library. Your file is read from disk into memory; it is never transmitted over the network. You can disconnect from the internet after loading this page and the tool will still work.