Choose a PDF to see every page's dimensions in points, inches and millimetres, with the nearest standard paper size and orientation.
The detector opens the PDF with pdf.js and reads each page's viewport at scale 1, which reports the page box in PDF points (72 points to an inch). Sizes are converted to inches and millimetres and matched against standard paper sizes — Letter, Legal, Tabloid, A3, A4, A5 and A6 — accepting the closest match within a small tolerance for rounding in real files. Orientation is portrait when the height is greater than the width, landscape when the width is greater, and square when they are equal.
What is a PDF point? A point is 1/72 of an inch. PDF page dimensions are stored in points, so a US Letter page measures 612 by 792 points.
Why does a page show no standard size? Not every PDF uses a paper size — slides, labels, receipts and cropped documents often have custom dimensions. The nearest standard name is shown only when a page is within tolerance of one.
Is the PDF uploaded? No. The file is read locally in the browser with pdf.js and never leaves the device.