DPI (Dots Per Inch)
A measure of image resolution — the number of dots of color packed into one inch of space. Higher DPI means more detail, larger file size.
DPI stands for Dots Per Inch — it describes how densely packed the pixels are in a printed or scanned image. 300 DPI means 300 dots of color in every inch; 72 DPI means 72. Higher DPI translates to sharper images and much larger file sizes.
Common DPI values
- 72 DPI — the traditional screen-resolution standard. Small file size, fine for on-screen reading but insufficient for print.
- 96 DPI — what Windows assumes for screen display. Slightly better than 72 for text clarity.
- 150 DPI — a good balance between quality and file size. Our default for PDF-to-image conversion.
- 300 DPI — the standard for professional print. Text is crisp, photographs look sharp even at large sizes.
- 600 DPI and above — archival quality, used by libraries and for highly detailed imagery. Very large files.
DPI and PDF
A PDF doesn't have a single DPI — different images inside it can have different resolutions. When you convert a PDF to an image (PDF to JPG or PDF to PNG), you choose the DPI at which to rasterize each page. When you compress a PDF, the tool often downsamples images to a target DPI to save space.
Choosing the right DPI
- For screen-only reading — 72 or 96 DPI is plenty
- For email attachments — 150 DPI balances quality and size well
- For printing — 300 DPI is the minimum for professional results
- For archival — 600 DPI or higher, depending on the source
Tools
- PDF to JPG and PDF to PNG — pick your DPI (72 / 150 / 300)
- Compress PDF downsamples image DPI to shrink file size