Why PNG: lossless means nothing is smudged
PNG stores every pixel exactly. When a page is saved as PNG, small text, thin table borders, signatures and QR codes stay crisp, and if you open and save the image again nothing is lost. JPG works differently: it throws away detail it thinks you will not notice, which leaves faint blocks and halos around black text on white paper. For a contract page, a form, a barcode or an engineering drawing, those artefacts can make a scan look poor or even stop a code from reading. That is the job of this page; for photos and colourful brochures, where smaller files matter more, the PDF to JPG converter is the better choice.
Transparent backgrounds from a PDF
Many PDFs do not paint a white page at all: the white you see is only how viewers display empty space. With "Transparent background" ticked, that empty space stays transparent in the PNG, so a logo, a stamp, a signature or a chart exported from design software can be placed on a coloured slide or website without a white box around it. If the PDF itself draws a white or coloured rectangle behind the content, as scanned documents and many word-processor exports do, that background is part of the page and stays. The tool cannot guess which white areas you want removed, so check one page first.
When PNG beats JPG, and when it does not
Choose PNG for screenshots of documents, slides with flat colours, diagrams, flowcharts, maps, sheet music, invoices you will crop later and anything you will edit again. Choose JPG when the page is mostly photographs, when an upload portal limits the file size, or when you are sending many pages over WhatsApp. A text page at 150 DPI is often a few hundred kilobytes as PNG; a photo-heavy page can be several megabytes, larger than the JPG of the same page.
Picking the DPI: pixel sizes you will get
DPI is the number of pixels made for each inch of the page, so the image size follows from the page size. An A4 page (8.27 × 11.69 inches) becomes about 595 × 842 pixels at 72 DPI, 1240 × 1754 at 150 DPI and 2480 × 3508 at 300 DPI; a US Letter page becomes 612 × 792, 1275 × 1650 and 2550 × 3300. Use 72 DPI for thumbnails, 150 DPI for screens, slides and websites, and 300 DPI when the PNG will be printed or zoomed. Each page's exact size is shown after the conversion. Very large pages are reduced slightly so your browser's memory can handle them, and the result tells you when that happens.
Private by design
The pages are drawn by pdf.js, the open-source engine in Firefox, inside this browser tab, and the PNG files are made on your device. Nothing is uploaded, there is no account and no watermark. Password-protected PDFs must be opened with their password first; the Unlock PDF tool can remove a password you know. If a PNG is too large to send, PNG to JPG makes a smaller file.