DPI calculator for printing: how many pixels you need
Type the print width and height, choose how far away people will look at it and add your image's pixels: the calculator tells you the resolution you need and whether your photo needs upscaling. Below, a ready-made table for the most common paper and poster sizes.
Calculator: the pixels your print needs
Rule of thumb: 300 ppi for things seen up close; further away needs less. Rounded up.
Upscale this imagePixels needed for common print sizes
| Format | Size (cm) | 300 DPI | 200 DPI | 150 DPI |
|---|---|---|---|---|
| A4 | 21 × 29.7 | 2,481 × 3,508 | 1,654 × 2,339 | 1,241 × 1,754 |
| A3 | 29.7 × 42 | 3,508 × 4,961 | 2,339 × 3,308 | 1,754 × 2,481 |
| A2 | 42 × 59.4 | 4,961 × 7,016 | 3,308 × 4,678 | 2,481 × 3,508 |
| A1 | 59.4 × 84.1 | 7,016 × 9,934 | 4,678 × 6,623 | 3,508 × 4,967 |
| A0 | 84.1 × 118.9 | 9,934 × 14,044 | 6,623 × 9,363 | 4,967 × 7,022 |
| 30 × 40 | 30 × 40 | 3,544 × 4,725 | 2,363 × 3,150 | 1,772 × 2,363 |
| 50 × 70 | 50 × 70 | 5,906 × 8,268 | 3,938 × 5,512 | 2,953 × 4,134 |
| 70 × 100 | 70 × 100 | 8,268 × 11,812 | 5,512 × 7,875 | 4,134 × 5,906 |
Pixels shown as width × height, rounded up.
DPI, PPI and why viewing distance matters
DPI (dots per inch) and PPI (pixels per inch) are used interchangeably when people talk about print resolution: both describe how many image pixels fall into each inch (2.54 cm) of paper. More pixels per inch means finer detail, but only up to the point where the eye can still tell them apart.
That point depends on distance. Something you hold in your hand, like a photo print or a flyer, needs around 300 PPI. A poster seen from about 1 m looks just as sharp at 150-200 PPI, and a banner viewed from several meters away is fine at 60-100 PPI. That is why the calculator asks for the viewing distance: printing a 5 m banner at 300 PPI only produces a huge file nobody will notice.
How to calculate print resolution by hand
The formula is simple: pixels = size in cm ÷ 2.54 × PPI. Divide by 2.54 to turn centimeters into inches, then multiply by the resolution you want.
- A 50 × 70 cm (about 20 × 28 in) poster at 150 PPI: 50 ÷ 2.54 × 150 = 2,953 px wide and 70 ÷ 2.54 × 150 = 4,134 px tall.
- The same poster at 300 PPI needs 5,906 × 8,268 px, four times as many pixels.
- A 200 × 100 cm banner seen from 3 m at 60 PPI: 4,725 × 2,363 px.
To check the other way round, divide your image's pixels by the PPI and multiply by 2.54: a 4,000 px wide photo gives 33.9 cm (13.3 in) at 300 PPI, or 67.7 cm at 150 PPI.
What to do if your photo is too small
If your image falls short, the only way to get more pixels with real detail is to upscale it. With the AI image upscaler you can enlarge it ×2 or ×4 for regular prints, and ×8, ×16 or Max for large format up to 600 megapixels; it will tell you whether the result reaches the PPI your size needs. For step-by-step advice on sharpening, file formats and what to send the printer, read our guide to upscaling an image for large-format printing, or go straight to upscaling a photo for A3, A2, A1 and canvas prints.
One common trap: changing the DPI value in Photoshop's Image Size dialog without resampling, or editing it in the file's metadata, does not add detail. It only changes the number the printer reads, so a 1,200 px photo labeled 300 DPI still prints at 10 cm wide, or prints larger and blurry.
RGB, CMYK and paper
Resolution is not the only thing a print shop checks. Most ask for a high-quality JPEG, PNG or PDF and convert your RGB image to CMYK themselves; bright blues and greens can look slightly duller on paper. Matte and canvas papers also soften fine detail, so a little less PPI than on glossy paper is usually invisible.
FAQ
How many pixels do I need for an A3 print at 300 DPI?
A3 is 29.7 × 42 cm (11.7 × 16.5 in), so at 300 DPI you need 3,508 × 4,961 pixels. At 200 DPI, 2,339 × 3,308 pixels are enough for a print viewed from a short distance.
Is 72 DPI good enough for printing?
No. 72 DPI is an old screen convention and the number alone means nothing: what matters is the pixel count. Divide your pixels by the print size in inches; if the result is below about 150 PPI for a poster or 300 PPI for a handheld print, the image will look soft.
What resolution do I need for a banner?
Banners are viewed from several meters away, so 60 to 100 PPI is usually enough. A 200 × 100 cm banner at 60 PPI needs 4,725 × 2,363 pixels.
What resolution is A4 at 300 DPI?
A4 is 21 × 29.7 cm, which at 300 DPI means 2,481 × 3,508 pixels when rounded up. Many guides round it to 2,480 × 3,508.
Does changing the DPI in Photoshop improve print quality?
Not on its own. Changing the DPI without resampling only changes how large the image prints; it adds no detail. To get more real pixels you need to upscale the image, for example with AI.