Photo Print Size Calculator
Check which standard photo sizes an image supports at your chosen DPI, from 4 x 6 inches up to 12 x 18 inches.
| Size | Needed pixels | Your effective DPI | Suitable? |
|---|---|---|---|
| 4 x 6 in | 1200 x 1800 | 750 DPI | Yes |
| 5 x 7 in | 1500 x 2100 | 600 DPI | No — image too small |
| 8 x 10 in | 2400 x 3000 | 375 DPI | No — image too small |
| 12 x 18 in | 3600 x 5400 | 250 DPI | No — image too small |
Suitability here is only about pixel count versus the chosen DPI. Viewing distance, printer capability and image content also affect the final print.
How to use this calculator
1. Enter image dimensions. 2. Pick a target DPI. 3. Read, for each preset size, the pixels required and whether your image meets them.
Formula
Effective DPI = Pixel width / Print width in inches. Compare it with your target DPI for each preset size.
Paper sizes and viewing distance
| Size | Millimeters | Pixels at 300 DPI |
|---|---|---|
| A5 | 148 x 210 mm | 1748 x 2480 px |
| A4 | 210 x 297 mm | 2480 x 3508 px |
| A3 | 297 x 420 mm | 3508 x 4961 px |
| Viewing situation | Target DPI | Why |
|---|---|---|
| Close-up photo | 300 | Held in the hand; fine detail is visible. |
| Wall poster | 150 | Viewed from a few feet away; finer detail cannot be resolved. |
| Billboard | 72 | Viewed from far away; 300 DPI would be wasted pixels. |
Frequently asked questions
Is a higher DPI always better?
Not by itself. DPI only matters together with pixel dimensions and print size. A small image printed very large will still look soft, even if you label it 300 DPI.
Does changing DPI metadata add detail?
No. Changing the DPI number in a file changes the intended print size, not the pixels. Detail only comes from having enough pixels.