DPI (dots per inch) is the print resolution of an image. Screen images are typically 72 or 96 DPI — far too low for print. Printers require 300 DPI for photo-quality output. Here is how to increase image DPI online for free.
Understanding DPI vs Pixel Dimensions
DPI is a print-specific measurement. An image with 1200×1800 pixels can be printed at any DPI — the DPI value just determines the print size. At 300 DPI, this prints at 4×6 inches. At 72 DPI, the same pixel dimensions would print at 16.7×25 inches (but look terrible at that size because the pixels are too large).
Increasing DPI: Two Methods
| Method | Result | Quality |
|---|---|---|
| Change metadata only | Same pixels, different DPI tag | No change — just changes print size |
| Upscale pixel dimensions | More pixels at 300 DPI | Better quality, larger file |
Which Method to Use
- Just change the DPI tag: Use this if your image already has enough pixels but the DPI metadata says 72. Many print systems need 300 DPI in the metadata — changing this does not affect the actual image quality.
- Upscale the image: Use this if your image does not have enough pixels for the desired print size at 300 DPI. This adds pixels through upscaling.
How to Increase Image DPI Free
Upload your image to imgresizr.com. Open the Resize tool and look for the DPI/Resolution setting. Enter 300 as the target DPI. If you also need more pixels, enter the target print dimensions — the tool will calculate the required pixel count at 300 DPI and resize accordingly. Download as TIFF for the best print DPI metadata preservation, or JPG at 95% quality.
Increase image DPI to 300 for print-ready output at imgresizr.com — free, instant, no software required.