96, 150 or 300 dpi: choosing a resolution for PDF to JPG
A PDF page has no pixels of its own — it is described in physical units. When it becomes a JPG, something has to decide how many pixels to draw it with. That is what the dpi setting does.
What dpi means here
dpi (dots per inch) sets how many pixels each inch of the page gets. A page 8.27 inches wide (A4) drawn at 150 dpi is about 1240 pixels wide. Double the dpi and the image has twice as many pixels across and four times as many in total.
| Page | 96 dpi | 150 dpi | 300 dpi |
|---|---|---|---|
| A4 | 793 × 1123 px | 1240 × 1754 px | 2479 × 3508 px |
| US Letter | 816 × 1056 px | 1275 × 1650 px | 2550 × 3300 px |
In the settings panel, each of Compact, Standard and High shows these numbers for your own first selected page before you save.
Which one to use
| You want to… | Start with |
|---|---|
| Look at the page on a screen, paste it into a message or a slide | 96 or 150 |
| Keep a readable copy of a text page, share it in a chat app | 150 (the default) |
| Keep small print and fine lines legible when zooming in | 300 |
| Print the image at the page’s original size | 300 |
These are starting points, not rules. If the text looks soft when you zoom in, go up a step; if the file is bigger than you need, go down one.
Higher is not automatically better
- File size. Four times the pixels usually means a much larger file, especially for scanned or photo-heavy pages.
- Work for your device. Every page is drawn in your browser. A long document at 300 dpi takes longer and needs more memory than the same document at 150 dpi.
- It cannot add detail that isn’t there. A scan made at 100 dpi does not gain sharpness when it is drawn at 300 dpi; the pixels only get bigger.
When the number you chose is not the number you get
To keep memory in check, a single page is limited to 8192 pixels on its longest side and 24 megapixels in total. A normal A4 or Letter page stays well below this at 300 dpi. Very tall or very large pages can reach it: a long, receipt-shaped page may come out at around 99 dpi at both the 150 and 300 settings.
When that happens, the page is scaled down with its proportions kept. Before you save, a note under the page selection tells you that a selected page will be scaled down and names the lowest resolution that will actually be used; the settings panel shows the same note.
dpi is not JPG quality
dpi decides how many pixels there are. JPG compression decides how those pixels are stored. The two are separate: a high-dpi image with strong compression can still look worse than a lower-dpi one with light compression. In PDF to JPG, JPG quality is preset; resolution is the setting you choose. How JPG quality and file size relate goes into this.
Convert your pages in the browser → PDF to JPG