Print resolution: dpi, ppi and pixels
For print, images should have about 300 dpi at their final size. An A4 image needs 2480 × 3508 pixels for that. Posters viewed from one or two metres away get by with 150 dpi, and large banners with even less.
Contents of this page
Telling dpi, ppi and lpi apart
- ppi (pixels per inch)
- How many pixels of a file fall on one inch (2.54 cm). This is the value you see in Photoshop or GIMP.
- dpi (dots per inch)
- Strictly, the number of dots a printer places. In everyday use, dpi almost always means the same as ppi, and that is how this page uses it too.
- lpi (lines per inch)
- The screen ruling in offset printing. 150 lpi is typical. As a rule of thumb, an image needs about twice the screen ruling, which is where 300 dpi comes from.
One thing matters above all: resolution always refers to a particular size. An image of 2480 × 3508 pixels has exactly 300 dpi at A4. Stretch it to A3 in your layout and you are down to 212 dpi. Programs such as InDesign show this “effective resolution” in the Links panel.
Pixels for every A size
| Size | 72 dpi | 150 dpi | 300 dpi | Megapixels at 300 dpi |
|---|---|---|---|---|
| A0 | 2384 × 3370 px | 4967 × 7022 px | 9933 × 14,043 px | 139.5 MP |
| A1 | 1684 × 2384 px | 3508 × 4967 px | 7016 × 9933 px | 69.7 MP |
| A2 | 1191 × 1684 px | 2480 × 3508 px | 4961 × 7016 px | 34.8 MP |
| A3 | 842 × 1191 px | 1754 × 2480 px | 3508 × 4961 px | 17.4 MP |
| A4 | 595 × 842 px | 1240 × 1754 px | 2480 × 3508 px | 8.7 MP |
| A5 | 420 × 595 px | 874 × 1240 px | 1748 × 2480 px | 4.3 MP |
| A6 | 298 × 420 px | 620 × 874 px | 1240 × 1748 px | 2.2 MP |
| A7 | 210 × 298 px | 437 × 620 px | 874 × 1240 px | 1.1 MP |
| A8 | 147 × 210 px | 307 × 437 px | 614 × 874 px | 0.5 MP |
| Letter | 612 × 792 px | 1275 × 1650 px | 2550 × 3300 px | 8.4 MP |
These values do not include bleed. With 3 mm of bleed, each side gains about 35 pixels at 300 dpi. For your own values, use the pixels to cm converter.
How much resolution for which viewing distance?
From further away, the eye resolves less detail. That is why a poster at a bus stop needs far fewer dpi than a photo in a photo book. The values below are tried and tested in practice:
| Product | Typical viewing distance | Recommended resolution |
|---|---|---|
| Business card, flyer, photo book | 30 cm | 300 dpi |
| Poster A2 to A0 | 1 to 2 m | 150 to 200 dpi |
| Roll-up banner, exhibition wall | 2 to 4 m | 100 to 150 dpi |
| Banner on a site fence | 5 m or more | 50 to 100 dpi |
| Billboard | 10 m or more | 20 to 50 dpi |
What does not work: upscaling
An image without enough pixels does not get better if you simply enter 300 dpi in Photoshop and let it resample. The program invents in-between pixels, but no detail. Modern AI upscalers can give surprisingly good results with photos, but the detail they add is invented as well. With product shots or portraits, check the result closely.
Vector graphics (logos, type, charts as PDF, EPS or SVG) have no fixed resolution and stay sharp at any size. So avoid placing logos as JPGs in a print file whenever you can.
What about screens? The 72 dpi myth
On screens, dpi plays no part. Only the number of pixels counts. An image 1200 pixels wide is 1200 pixels wide on a web page, whether the file says 72 or 300 dpi. The 72 dpi figure goes back to the early Macintosh, whose screen had exactly 72 dots per inch. Windows assumed 96 dpi. Modern displays are usually far higher.
Line art needs more
Pure black and white graphics with no greys, such as scanned signatures, plans or line drawings, are not screened in print. To keep their edges from looking jagged, they should have 1200 dpi. For greyscale and colour images, 300 dpi is enough.
Frequently asked questions
How many pixels does an A4 image need for print?
2480 × 3508 pixels for 300 dpi. With 3 mm bleed, 2551 × 3579 pixels.
Is 150 dpi enough for print?
For posters and large formats seen from a distance, yes. For flyers, business cards and photo books, 300 dpi is better.
What is the difference between dpi and ppi?
ppi describes the pixels in a file, dpi the dots a printer places. In everyday use, the two terms mean the same.
Can I upscale an image to 300 dpi?
Technically yes, but no new detail appears. The image looks soft or blurred.