When you convert a PDF to JPG or PNG, DPI controls how large and detailed the output image becomes. A higher DPI gives you more pixels and sharper detail, but it also creates larger files. A lower DPI creates smaller files, but the image may not be as clear when viewed closely or printed.
The best DPI depends on what you want to do with the converted image. For most people, 150 DPI is the best default.
What does DPI mean?
DPI stands for dots per inch. In PDF-to-image conversion, it is a practical way to control output resolution. Higher DPI means the PDF page is rendered into a larger image. Lower DPI means the page is rendered into a smaller image.
You do not need to think about this too technically. Just remember the trade-off: higher DPI means sharper images and larger files; lower DPI means smaller files and less detail.
Quick recommendation
| DPI | Best for | Why |
|---|---|---|
| 72 DPI | Small previews, thumbnails and quick web use | Keeps files light and fast. |
| 150 DPI | Everyday conversion | Good balance between readability and file size. |
| 300 DPI | Print, detailed pages and professional use | Produces larger, sharper images. |
| Custom DPI | Special workflows | Useful when a platform or print process requires a specific size. |
When to use 72 DPI
Use 72 DPI when you only need a lightweight preview. This can be useful for thumbnails, quick visual references, draft uploads or situations where image size matters more than fine detail.
It is not the best choice if the PDF contains small text or if the image will be printed. It is meant for speed and small files, not maximum clarity.
When to use 150 DPI
Use 150 DPI for most normal conversions. It usually gives a readable, clean image without making the files unnecessarily large. If you are converting pages for email, internal documentation, presentations, web content or general sharing, 150 DPI is the safest starting point.
This is why 150 DPI is often the “sweet spot”. It is clear enough for everyday use and still practical for multi-page PDFs.
When to use 300 DPI
Use 300 DPI when quality matters more than file size. This is the better choice for printing, archiving important pages, zooming in on detail or creating images that need to look sharp in a professional layout.
The trade-off is file size. A 300 DPI image can be much larger than a 150 DPI image, especially if the PDF has many pages. If you convert a long PDF at 300 DPI, expect a bigger ZIP file and longer processing time.
DPI and file format
DPI is only one part of the result. The output format also matters. JPG usually creates smaller files and is good for photos or scanned pages. PNG usually creates sharper-looking text and diagrams, but the files can be larger.
| Goal | Suggested settings |
|---|---|
| Small web preview | JPG, 72 DPI |
| General document sharing | JPG or PNG, 150 DPI |
| Sharp text or diagrams | PNG, 150 DPI |
| Print-quality output | PNG or JPG, 300 DPI |
| Scanned receipt or invoice | JPG, 150 DPI |
| Technical documentation | PNG, 150 or 300 DPI |
Not sure about format? Read PDF to JPG or PNG.
A simple decision rule
If you are not sure, start with 150 DPI. If the image looks too soft, try 300 DPI. If the file is too large and you only need a preview, try 72 DPI.
That small test usually tells you everything you need to know.
Sensitive or private PDFs
If your document is private, confidential or work-related, use the desktop app to convert it offline. That way, you can choose the right DPI without uploading the PDF through a browser.