PDF to JPG Resolution and Quality: 72, 144 or 216 DPI?

People often use the words interchangeably, but they control different things. Resolution is how many pixels the finished image contains, its width and height. Quality is how aggressively the JPG compression throws away fine detail to save space.

You can have a large image at low quality (many pixels, visible compression noise) or a small image at high quality (few pixels, but clean). Getting a result you are happy with means setting both for the job at hand.

A PDF page has a physical size measured in points, where one point is 1/72 of an inch. An A4 page is about 595 by 842 points and a US Letter page is 612 by 792 points. At 1x the converter draws one pixel for every point, so the image has 72 pixels per inch. At 2x it draws two pixels per point (144 pixels per inch), and at 3x three (216 pixels per inch). People usually call this DPI, though strictly it is pixels per inch.

JPG compresses by simplifying small blocks of the image. The lower the quality, the more it simplifies, and the smaller the file becomes. The converter offers three levels:

• Low, the smallest files. Fine for previews and chat, but fine text can look slightly fuzzy.
• Medium, the sweet spot for most documents. Files stay reasonable and text remains clean at normal viewing size.
• High, keeps the most detail with only mild compression. Choose it for diagrams, small print or images you will crop and reuse.

Text pages are less forgiving than photos. Compression noise shows up as faint speckles around black letters on a white page, while a photograph hides the same noise in its texture. If a page is mostly text or line art, lean towards higher quality, or look at PDF to PNG, which uses no lossy compression at all.

• Email or chat attachment: 1x or 2x, low or medium quality. Small, quick to send.
• Website or blog images: 2x, medium quality, then run the files through the Image Compressor for an extra size reduction.
• Slides and documents: 2x, medium quality. This is sharp on a full-HD screen without bloating the presentation.
• Social media: 2x, medium quality. Platforms re-compress uploads anyway, so extra quality is wasted.
• Reading small print on a phone: 3x, high quality so zooming stays crisp.
• Text recognition (OCR): 3x, high quality. Sharper letters give Image to Text a better chance of reading them correctly.

A scanned PDF is really a photograph of paper stored inside a PDF. If the scan was made at 300 pixels per inch, an A4 page already holds roughly 2480 by 3508 pixels. Converting it at 3x (1785 by 2526 pixels) actually reduces some detail, so use the highest setting for scans.

The opposite is also true. A low-resolution scan cannot be sharpened by converting it at 3x; you just get a bigger file of the same blur. Check the quality of the original before you blame the converter.

Yes, with realistic expectations. Professional printing normally expects around 300 pixels per inch. The 3x setting gives 216, which looks fine on a home printer for drafts, handouts and reference copies, but is below that benchmark for glossy, close-up work.

If print quality matters, keep printing from the original PDF. A PDF stores text and vector graphics as shapes that stay sharp at any size, which a JPG cannot match. Use the JPGs when you need an image, not when you need the best possible print.

If your converted images are too large, work backwards through the same dials: drop to medium quality first, then step the resolution down from 3x to 2x. After conversion you can still trim size with the Image Compressor or reduce dimensions with the Image Resizer.

Troubleshooting a specific problem? Our guide to fixing blurry, oversized or blank PDF to JPG results covers the most common cases.