# What DPI will my print have?

Works out the print resolution in dots per inch (DPI) of an image from its pixels and the print size, the largest print at a target DPI, and the pixels a print size needs.

- Page: https://www.acalculator.org/logic/dpi-calculator
- JSON spec: https://www.acalculator.org/logic/dpi-calculator.json
- Version: ba208f30575f

## Default answer

Example with the default inputs (Image width (pixels) 3,000, Image height (pixels) 2,400, Print width 10 in, Print height 8 in, Target DPI 300): A 3,000 × 2,400 pixel image printed 10 in × 8 in has 300 DPI.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| pw | Image width (pixels) | The width of the image in pixels. |
| ph | Image height (pixels) | The height of the image in pixels. |
| w | Print width | The width of the print. |
| h | Print height | The height of the print. |
| t | Target DPI | The resolution you want the print to have: 300 is a common choice for photos. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| dpi | Print resolution | The lower of the DPI across and down: what the whole print gets. |
| dpiWidth | DPI across | Image width in pixels ÷ print width in inches. |
| dpiHeight | DPI down | Image height in pixels ÷ print height in inches. |
| maxWidthIn | Largest print width at the target (in) | Image width ÷ target DPI, in inches. |
| maxHeightIn | Largest print height at the target (in) | Image height ÷ target DPI, in inches. |
| maxWidthCm | Largest print width at the target (cm) | Image width ÷ target DPI × 2.54, in centimetres. |
| maxHeightCm | Largest print height at the target (cm) | Image height ÷ target DPI × 2.54, in centimetres. |
| needWidth | Pixels needed across | Print width × target DPI, rounded up. |
| needHeight | Pixels needed down | Print height × target DPI, rounded up. |
| enough | Meets the target? | Yes when the print resolution is at least the target DPI. |

## Method

DPI across = pixel width ÷ print width (in); DPI down = pixel height ÷ print height (in); print resolution = the lower; largest print = pixels ÷ target DPI; pixels needed = ⌈print size (in) × target DPI⌉.

## Assumptions

- The image fills the print without cropping or borders; when its shape differs from the print, the lower DPI applies to the whole print.
- DPI here means image pixels per printed inch (also called PPI); a printer’s own ink dots per inch are a separate setting.

## Worked examples

1. pw = 3,000, ph = 2,400, w = 0.254, h = 0.2032, t = 300 gives dpi = 300, dpiWidth = 300, dpiHeight = 300, needWidth = 3,000, needHeight = 2,400, enough = Yes. Source: ScanTips, Printing and Scanning Resolution DPI Calculator (print size = pixels ÷ resolution), https://www.scantips.com/calc.html (3,000 pixels at 300 dpi prints 10 inches).
2. pw = 1,500, ph = 1,200, w = 0.254, h = 0.2032, t = 300 gives dpi = 150, maxWidthIn = 5, maxHeightIn = 4, maxWidthCm = 12.7, enough = No. Source: ScanTips, Printing and Scanning Resolution DPI Calculator (print size = pixels ÷ resolution), https://www.scantips.com/calc.html.
3. pw = 4,000, ph = 3,000, w = 0.2, h = 0.15, t = 300 gives dpi = 508, needWidth = 2,363, needHeight = 1,772. Source: ScanTips, Printing and Scanning Resolution DPI Calculator (print size = pixels ÷ resolution), https://www.scantips.com/calc.html.
4. pw = 3,000, ph = 2,000, w = 0.254, h = 0.2032, t = 300 gives dpiWidth = 300, dpiHeight = 250, dpi = 250, enough = No. Source: ScanTips, Printing and Scanning Resolution DPI Calculator (print size = pixels ÷ resolution), https://www.scantips.com/calc.html.

## FAQ

### How do I calculate DPI for printing?

Divide the image’s pixels by the print size in inches. A 3000 × 2400 pixel image printed 10 × 8 in has 3,000 ÷ 10 = 300 dots per inch across and 2,400 ÷ 8 = 300 down.

### How big can I print an image at 300 DPI?

Divide each pixel count by 300. A 1500 × 1200 image prints 5 × 4 in at 300 DPI; at 150 DPI it prints 10 × 8 in, with fewer pixels in each inch.

### What DPI do I need for a good print?

300 DPI is a common target for photos and small prints viewed up close. Large posters and banners viewed from a distance often look fine at 150 DPI or less. Set the target DPI to what your printer or print shop asks for.

### Why are the DPI across and down different?

The image and the print have different shapes. A 3000 × 2000 (3:2) image on an 8 × 10 print gets 300 DPI across but only 250 DPI down, so the page reports the lower value; in practice the image is cropped or gets a border.

### Is DPI the same as PPI?

For sizing an image, people use the two words for the same thing: image pixels per printed inch. Strictly, PPI is pixels and DPI is the ink dots a printer lays down. For a screen’s pixel density, use the PPI calculator; for mouse sensitivity, the eDPI calculator.

### Does changing the DPI setting in my photo editor change the image?

Not if you only change the DPI number without resampling. The pixels stay the same; only the print size the file asks for changes. Adding pixels by resampling cannot add real detail.

## Sources

- ScanTips, Printing and Scanning Resolution DPI Calculator: print size in inches = pixels ÷ resolution (3,000 pixels at 300 dpi print 10 inches). https://www.scantips.com/calc.html (retrieved 2026-10-01)
- NIST Special Publication 811, Appendix B: 1 in = 2.54 cm = 25.4 mm exactly. https://www.nist.gov/pml/special-publication-811 (retrieved 2026-10-01)