What does dpi mean for print?
In short
DPI (dots per inch) is the resolution of an image at the size it prints. Print files need 300dpi at the printed size, or 150dpi on large items such as A1 and A0 posters, correx boards and roller banners.
DPI, or dots per inch, describes how many image pixels land in each inch of the printed item. Strictly, image files are measured in pixels per inch (ppi), but most people and most software say dpi for both. What counts is how many pixels the image has compared with the size it will print.
How much you need
| Item | Resolution at the printed size |
|---|---|
| Business cards, leaflets, booklets, stickers and stationery | 300dpi |
| A3 and A2 posters | 300dpi |
| A1 and A0 posters | 150dpi |
| Correx boards and roller banners | 150dpi |
Large items are seen from further away, so 150dpi at full size looks sharp on them.
Working out the pixels
Divide the printed size in millimetres by 25.4 to get inches, then multiply by the dpi. A business card with bleed (91 x 61mm) at 300dpi needs about 1075 x 720 pixels. An A1 poster (594 x 841mm) at 150dpi needs about 3508 x 4967 pixels.
Typing a bigger number doesn't add detail
Changing the resolution box from 72 to 300 without adding pixels just shrinks the image or leaves it soft. A picture saved from a website or social media is rarely big enough for a poster or banner. Use the original file from the camera, phone or designer, and check it at 100% zoom. Our free automatic check looks at image resolution on every upload.