PDF or JPG: which format should you use for documents?

The short answer

Use PDF for documents and JPG for photos. A PDF is a container for pages: it can hold many pages, real text, vector drawings and images, and it keeps a fixed page size so it prints the way it looks. A JPG is a single picture, compressed in a way that works brilliantly for photographs and less well for sharp edges.

The exceptions come mostly from upload forms and from how the recipient will use the file, as the sections below explain.

When PDF is the better choice

Pick PDF whenever a document has more than one page, contains real text or is going to be printed. It is the safer default in these situations:

• Multi-page documents. One PDF keeps a contract, a report or a bundle of receipts together in the right order, instead of a pile of separate images.
• Anything with real text. Documents exported from a word processor stay sharp at any zoom level, and the text can be searched and copied.
• Printing. PDF pages carry an exact size such as A4 or US Letter, so the printout matches the screen.
• Formal submissions. Many employers, universities and offices expect PDF and treat it as the standard for official paperwork.
• Fillable forms. Form fields only exist in PDFs; a JPG of a form is just a picture of one.

When JPG is the better choice

JPG wins when the content is a picture, or when the place you are sending it wants an image. If a portal says JPG or JPEG, give it exactly that, because many systems check the file type and reject anything else.

• Photos. Pictures of people, places and objects are what JPG was designed for, and they stay small with little visible loss.
• Upload fields that ask for an image, such as a passport photo, a signature or a profile picture.
• Quick sharing in chats and social apps, where an image preview appears instantly and a PDF may need an extra tap to open.
• Embedding a page in a slide, a website or another document that accepts images but not PDFs.

Quality and file size trade-offs

JPG uses lossy compression: it throws away detail the eye is unlikely to notice. That makes photos small, but around sharp black text on white paper it can leave faint smudges, called artifacts, especially at low quality settings. Every time a JPG is edited and saved again, a little more detail is lost.

A PDF's size depends on what is inside it. A text-based PDF is often far smaller than a JPG of the same page, because letters are stored as characters rather than pixels. A PDF made from photos is roughly as large as the photos it contains. Putting a JPG into a PDF does not make it bigger or smaller by much; the PDF simply wraps the image.

PNG for screenshots and line art

PNG is the third format worth knowing. It is lossless, so every pixel is kept exactly, which makes it the best choice for screenshots, charts, diagrams, logos and signatures on a transparent background. Small text in a PNG screenshot stays crisp where a JPG might blur it.

The trade-off is size. A photo saved as PNG can be several times larger than the same photo as JPG. As a rule of thumb, use PNG when the image has flat colours and hard edges, and JPG when it looks like a photograph.

Converting between formats

PDFHomebase has a tool for each direction, and all of them run in your browser.

• PDF to JPG: turns each page, or only the pages you pick, into images. Choose JPG for scans and photo pages, or PNG for text and diagrams. Several pages download together as a ZIP.
• JPG to PDF: combines one or more photos into a single PDF, with a choice of page size, orientation and margins. It also accepts PNG, WebP and GIF.
• PNG to PDF: the same converter set up for lossless images, keeping screenshots and diagrams pixel-perfect inside the PDF.

Choosing the right resolution

When you convert a PDF page to an image, resolution is measured in dots per inch. At 150 dpi, an A4 page becomes about 1240 by 1754 pixels, which is sharp on phones and monitors and keeps files manageable for email and uploads. At 300 dpi it becomes about 2480 by 3508 pixels, the usual standard for printing, with files roughly four times larger. 72 dpi is only good for thumbnails and previews.

The same numbers apply in reverse when you scan. Scan at 150 to 200 dpi for documents you will only read on screen, and at 300 dpi if you expect to print them or need fine print to stay legible. Going higher rarely helps documents and makes files much heavier.

Tools used in this guide

• PDF to JPGTurn PDF pages into high-quality JPG or PNG images.
• JPG to PDFTurn photos and images into a single PDF, in any order.
• PNG to PDFTurn PNG screenshots and graphics into a PDF without losing quality.
• Compress PDFShrink PDF file size while keeping it readable. Never makes a file bigger.

Frequently asked questions