Image DPI Calculator
Pixels Are Not Inches Until DPI Says So
A digital image file has a pixel count and nothing else — it only becomes a physical size once you decide how many of those pixels get packed into each printed inch. That density is DPI (dots per inch, though pixels per inch is the more technically accurate term for a digital file). This calculator runs the relationship in both directions: given pixels and a target print size, find the DPI you'll get, or given a target DPI and print size, find the pixel resolution you need to capture or export.
The Formula
Find Required Pixels: Required Pixels = Print Dimension (inches) × Target DPI
Width and height are calculated independently, then compared — if they land far apart, the image's pixel aspect ratio doesn't match the target print's aspect ratio, and cropping will be required to fill the frame without distortion.
Where This Calculation Matters
- Print ordering — checking that a file has enough resolution before sending it to a lab avoids a soft, pixelated print.
- Stock photography submission — agencies commonly require a minimum pixel resolution tied to an assumed print DPI.
- Scanning workflows — choosing a scan DPI that captures enough data for the largest print planned from that scan.
- Design handoff — confirming a supplied image meets the resolution a print designer specified for a layout.
Standard DPI Reference Points
| Output | Typical DPI |
|---|---|
| Web / screen display | 72–96 |
| Draft or proof print | 150 |
| Standard photo print | 300 |
| Large-format poster (viewed at distance) | 100–150 |
| Fine-art or gallery print | 300–600 |
Large-format prints can use lower DPI than expected because viewing distance increases with print size, which reduces the resolution the eye can actually resolve.
How to Use This Calculator
- Choose a mode: Find DPI or Find Required Pixels.
- In Find DPI mode, enter the image width and height in pixels, then the target print width and height in inches.
- In Find Required Pixels mode, enter the target print width and height in inches, then the target DPI.
- Select Calculate to get the result.
Related Calculations
For the same math specialized around a target DPI and pixel count, see the Print Size DPI Calculator. To estimate the resulting file size at your resolution, use the Image Compression Calculator.