Converting a PDF page to a JPG sounds simple until you meet the DPI setting. DPI means dots per inch: how many pixels the converter creates for each inch of the page. Pick too low a number and the image looks blurry. Pick too high a number and you get an enormous file that is slow to share and no sharper on screen than a smaller one would have been. The right choice depends on what the image is for, not on picking the biggest number available.

PDF to JPG renders every page of a PDF as a numbered JPG at 72, 150, 200, or 300 DPI, with an adjustable quality setting, entirely in your browser. When there are several pages, the results arrive zipped. Understanding the four DPI options before you convert will save you a second conversion and a bloated file.

What DPI actually changes

A PDF page has a physical size, usually A4 or Letter, and DPI decides how many pixels represent that size. At 72 DPI, an A4 page becomes roughly 595 by 842 pixels. At 150 DPI it becomes about 1240 by 1754 pixels. At 300 DPI it is roughly 2480 by 3508 pixels. The text and pictures do not change; they are simply drawn with more pixels, which makes edges smoother and small print easier to read, at the cost of a larger file.

This matters because screens and printers use pixels differently. A screen shows an image at its pixel size, so a 595-pixel-wide image fills only part of a modern display and looks soft when stretched. A printer, on the other hand, can use the extra pixels from a 300 DPI image to produce crisp print. The same JPG can therefore be perfect for one purpose and wrong for another, which is why the setting exists at all.

Quality is a separate control from DPI. DPI sets the pixel dimensions; quality sets how aggressively the JPG compression discards detail to shrink the file. A high-DPI image saved at low quality can look worse than a lower-DPI image saved at high quality, so if a result looks poor, check both settings before blaming one of them.

72 DPI: quick previews and small screens

At 72 DPI, images are small and fast. They suit quick previews, thumbnails, and situations where the image will be shown small — a chat message preview, a rough draft for checking layout, or a page you want someone to glance at rather than read closely. The file sizes stay modest, which helps when you are sending many pages or working on a slow connection.

The limit is readability. Body text at 72 DPI is often readable when shown at its natural size, but small print, footnotes, and fine table lines can blur. If the reader needs to read the page properly, rather than recognise what it is, 72 DPI is usually too low. Use it for identification, not for reading.

150 and 200 DPI: the everyday middle ground

For most screen purposes, 150 DPI is the sensible default. The image is large enough to read comfortably on a laptop or tablet, including ordinary body text, without the file becoming unwieldy. Slides, social posts, and documents shared for reading on screen generally sit happily at 150 DPI.

200 DPI is the step up when the page contains small text, detailed diagrams, or tables with fine lines. It gives those details more room without jumping to the much larger files that 300 DPI produces. If you are unsure between two settings, 200 DPI is a safe middle choice: noticeably sharper than 150 for dense pages, but still manageable to share.

300 DPI: print and fine detail

300 DPI is the print standard, and it is the right choice when the JPG will be printed, or when the page must be read at fine detail — a scanned form with small handwriting, a technical drawing, or a page that will be cropped and enlarged later. The files are large, often several megabytes per page, so converting a long document at 300 DPI produces a heavy download. That is a fair trade when print quality is the goal, and a waste when the image will only ever be viewed on a phone screen.

A common mistake is converting everything at 300 DPI "just in case". The extra pixels do not improve a screen image beyond a certain point, because the screen cannot show them all, and they slow down sharing, uploading, and loading. Choose 300 DPI deliberately, for print or for detail, not by default.

Worked example: one fictional page at four settings

Take a fictional one-page newsletter for a neighbourhood garden group, invented for this example. The author, a fictional volunteer named Tom, shares it at tom@example.org. The page has a headline, two columns of body text, a small table of meeting dates, and a photograph of a garden bed. Converted at 72 DPI, the headline and photograph are clear, but the table dates are hard to read. At 150 DPI, the body text reads comfortably and the table is legible. At 200 DPI, the table's fine lines sharpen further, and the photograph shows more texture. At 300 DPI, the print version is crisp, but the file is several times larger than the 150 DPI version, with no visible gain when viewed on a laptop screen.

Tom's sensible choice depends on the audience. For emailing the newsletter to members who will read it on their phones, 150 DPI is enough. For printing copies for a noticeboard, 300 DPI is worth the larger file. For slides showing the table, 200 DPI gives the detail without the bulk. The same page, three audiences, three different settings — which is why a converter that offers the choice is more useful than one that picks a single DPI for you.

If the JPGs then need resizing or format changes, Image Optimizer can handle that batch, and if the original pages came from photographs, JPG to PDF runs the opposite direction, combining images into a single PDF.

Honest limitations

Converting a PDF page to a JPG turns text into pixels. The resulting image cannot be searched, copied, or read aloud by a screen reader in the way the original PDF text could. That loss is permanent for that JPG: if you later need the text, you must go back to the original PDF. JPG compression also discards some detail by design, so a JPG will never be a perfect copy of a vector PDF page, however high the DPI. For pages where the text must stay selectable, keep the PDF and share that instead.

Very high DPI settings also have practical limits. Large images take longer to render, use more memory in the browser, and can be slow on older devices. If a conversion feels sluggish, dropping from 300 to 200 DPI is often the simplest fix.

For choosing between image formats more broadly, see the image format guide.

FAQs

What DPI should I use for slides?

150 DPI is usually enough for slides, because slides are viewed on screen and often at reduced size. Use 200 DPI if the slide shows a dense table or small text that the audience must read.

Why do my converted JPGs look blurry?

Usually the DPI was too low for how the image is being shown, or the quality setting was low. Try a higher DPI first, and if the image is shown large, check that it is not being stretched beyond its pixel size.

Can I convert all pages of a PDF at once?

Yes. PDF to JPG renders every page as a numbered JPG, and when there are several pages the results arrive as a ZIP file, so you do not need to convert page by page.

Is 300 DPI always better than 150 DPI?

No. It is better for print and fine detail, but for screen viewing it mostly produces a larger file with no visible improvement. Match the DPI to the purpose: screen, slides, or print.

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