What this calculator does
Print resolution, expressed in dots per inch (DPI), is how densely an image file’s pixels are packed onto a printed page. The same image file can be printed at a high DPI on a small print or a much lower DPI if blown up to a large size, since the pixel count is fixed but the physical size it is spread across is not.
Photographers typically work with a target DPI in mind, commonly around 300 for fine-detail prints viewed up close and lower figures such as 150 for large prints viewed from further away, and then work out the biggest size a given image can be printed at while still meeting that target.
The formula
DPI is the image’s pixel dimension divided by the print size in inches along that same dimension. Working the other way, the maximum print size at a target DPI is the pixel dimension divided by that target DPI.
| Term | Meaning |
|---|---|
| DPI | Dots per inch: how many pixels are printed per inch of physical paper. |
| Target DPI | The DPI you want the print to meet, commonly 300 for high-detail work or 150 for large-format prints. |
| Maximum print size | The largest a print can be while still meeting the target DPI: pixel dimension ÷ target DPI. |
The inputs explained
| Field | What to enter |
|---|---|
| Image width (pixels) | The width of the image file in pixels. |
| Image height (pixels) | The height of the image file in pixels. |
| Target print width (inches) (in) | The width you want to print at, in inches. |
| Target print height (inches) (in) | The height you want to print at, in inches. |
| Target DPI for maximum print size (e.g. 300 high quality, 150 good) | The DPI you want the print to achieve, such as 300 for high quality or 150 for good quality at larger sizes. |
When to use it
Ordering a print at a specific size
Before ordering a large print, checking the resulting DPI against the image’s pixel dimensions confirms whether the file has enough resolution for that size without looking soft.
Deciding the biggest usable print from a file
Working out the maximum print size at a chosen target DPI answers the common question of how big a given photo can go before it starts to lose sharpness.
Choosing camera settings for an intended print
Knowing the print size and DPI needed in advance helps decide what resolution setting to shoot at, rather than discovering after the fact that a file falls short.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How resulting DPI changes with print size at a fixed image resolution
A fixed 6000 × 4000 pixel image, printed at a range of widths (height scaled to match).
How maximum print size changes with target DPI at a fixed image resolution
The same 6000 × 4000 pixel image, against a range of target DPI values.
| Target DPI | Max print size at target DPI |
|---|---|
| 150 | 40.00 × 26.67 in |
| 200 | 30.00 × 20.00 in |
| 240 | 25.00 × 16.67 in |
| 300 | 20.00 × 13.33 in |
| 360 | 16.67 × 11.11 in |
Questions
What DPI do I actually need?
It depends on viewing distance: 300 DPI is a common standard for prints viewed up close, such as photo books or small prints, while large-format prints viewed from further away, such as posters or billboards, can look sharp at well under 150 DPI because the viewer is never close enough to see the individual dots.
Is DPI the same as PPI?
They are often used interchangeably in photography, though strictly PPI (pixels per inch) describes the image file and DPI describes the printer’s dot output. For practical print-planning purposes, treating them as the same figure is standard practice.
What happens if I print below my target DPI?
The print is not physically damaged, but detail can look softer or slightly pixelated up close, especially in areas with fine texture or text. Whether it is noticeable depends heavily on viewing distance and the subject matter.
Can I upscale an image to hit a higher DPI?
Software upscaling can increase the pixel dimensions of a file, but it invents detail rather than recovering it, so results vary. It is not equivalent to having genuinely captured more resolution in the original shot.
For working out the storage a full shoot of prints and video will need, see the photo shoot storage calculator.