DPI vs PPI: the real difference for prints

4 hours ago
4 min read

You’ve heard it a thousand times: “Use 300 DPI for print.” Close… but not quite. For photography and print, PPI and DPI are not the same thing, and mixing them up leads to soft prints, bloated files, and confused clients. Here’s the practical breakdown, with a print‑size table you can paste into your workflow.

A collection of printed images showcases various dishes held by colorful forks against a dark background.

TL;DR

PPI = pixels per inch. It belongs to your image and controls how many image pixels you place per printed inch. It sets printable size at a given quality.
DPI = dots per inch. It belongs to the printer and controls how densely the device sprays dots of ink or toner. Printers expose multiple dots to render each image pixel.
For photo‑quality prints, aim for 300 PPI at final size when possible. You can go lower for big pieces viewed from farther away.
For the web, PPI/DPI metadata doesn’t change how big an image appears. Browsers map pixels to CSS pixels based on device pixel ratio, not the “72 PPI” myth.

PPI vs DPI

PPI answers: How many image pixels am I packing into each inch of paper? If you print a 3000 × 2400 px file at 300 PPI, you get a 10 × 8 in print. Double the PPI and the print gets smaller; halve the PPI and it gets larger. This is an image property and you control it in Photoshop, Lightroom, or your lab’s uploader.

DPI answers: How many physical ink dots does the device place per inch? Inkjet drivers expose settings like 720, 1440, 2880 dpi that affect dot placement and speed. DPI is about the device, not your image pixels.

DPI vs PPI, why people confuse them: A printer often needs several dots to render one pixel through dithering, so DPI numbers are much higher than the PPI you supply.

How much PPI do you actually need?

300 PPI is the industry shorthand for crisp photographic prints at close viewing distances. Adobe’s current guidance calls 300 pixels per inch the standard, and notes that ~220 PPI can still produce very good inkjet results.
Large prints can be lower because viewers stand back. Many posters look fine below 200 PPI at normal viewing distance. Cambridge in Colour emphasizes that viewing distance determines acceptable print resolution.
Photo books and consumer labs: you’ll see lab rules of thumb like 250–300 PPI minimums for page images.
Offset press work: match image PPI to the press line screen. A common rule is 1.5–2× LPI (lines per inch). For a 150 LPI magazine screen, 225–300 PPI at final size is typical. Adobe documents this relationship directly.

Printer DPI settings in context

Your printer’s DPI menu does not change your image’s pixel count. It changes how finely the device places dots. Higher DPI can add smoothness but slows printing and has diminishing returns. Examples from vendor docs show modes like 720, 1440, 2880 dpi with speed–quality tradeoffs.

Takeaway: set your image size in PPI for the final print dimensions, then pick a sensible printer DPI mode. Most photo inkjets look excellent at 1440 dpi modes; “max dpi” is often overkill for real photos.

The “72 PPI for web” myth, quickly debunked

Browsers ignore your file’s PPI tag and lay out images by pixel dimensions and CSS pixels. What matters is width × height in pixels and responsive markup, not a magic 72. Device pixel ratio decides how many hardware pixels represent a CSS pixel on a given screen.

Print‑size cheat sheet

Use this table to size image exports. The left column gives target pixel dimensions for common print sizes at 300 PPI and 240 PPI. Pick the row that matches your paper to know how big your file should be.

Print size (inches)	300 PPI (pixels)	240 PPI (pixels)
4 × 6	1200 × 1800	960 × 1440
5 × 7	1500 × 2100	1200 × 1680
8 × 10	2400 × 3000	1920 × 2400
Letter 8.5 × 11	2550 × 3300	2040 × 2640
11 × 14	3300 × 4200	2640 × 3360
12 × 18	3600 × 5400	2880 × 4320
16 × 20	4800 × 6000	3840 × 4800
18 × 24	5400 × 7200	4320 × 5760
20 × 30	6000 × 9000	4800 × 7200
24 × 36	7200 × 10800	5760 × 8640
30 × 40	9000 × 12000	7200 × 9600
A4 8.27 × 11.69	2480 × 3508	1984 × 2806
A3 11.69 × 16.54	3508 × 4961	2806 × 3969

Reference targets only. For wall art, you can often go lower due to viewing distance.

Copy‑paste export checklist

Pick your final print size and target PPI from the table.
In the editor, set PPI and document size. Avoid upsampling if you can.
For home inkjets, a 1440 dpi quality mode is usually the best balance of quality and speed.
Soft‑proof and sharpen for output, then export a high‑quality JPEG or TIFF for your lab. Adobe’s “Preparing images for press” page covers press specifics and why you should confirm requirements with the provider.

How to set PPI correctly in Photoshop

Open Image Size: Image → Image Size.
Uncheck Resample to change print size or PPI without changing pixel count.
Enter your desired Resolution (for example 300) and a Document Size.
If you must change the pixel count, enable Resample and choose “Preserve Details.” Adobe notes that upsampling adds pixels and may reduce detail.

Quick math for any print

PPI = pixels ÷ inches. Example: a 6000 px long edge printed at 20 in gives 300 PPI.
Pixels needed = inches × PPI. Example: 20 in at 300 PPI needs 6000 px. Adobe’s docs use this exact relationship.

FAQ

Is 300 PPI mandatory?

No, it’s a quality target. Adobe calls 300 PPI the standard, but also states ~220 PPI can be fine on many inkjets. Large prints can dip below 200 PPI if they’re viewed from afar.

Do I set DPI in Photoshop?

You set PPI in Photoshop. DPI is selected in the printer driver or by the lab and controls dot placement on paper.

Why does my lab ask for 300 DPI?

They usually mean 300 PPI at final size. Many labs and book tools flag images below 250–300 PPI because that’s a safe client‑friendly guideline.

Do PPI or DPI affect web SEO or layout?

No. On the web, use proper pixel dimensions, responsive srcset, and performance formats. PPI/DPI metadata doesn’t affect layout; device pixel ratio does.