When printing out an image, the resolution is measured in ink dots per inch (dpi). Therefore, when you are setting up a canvas that you want to later print you need to calculate the needed pixel size of your canvas for your preferred printing resolution (usually 150 or 300 dpi).
In Sketchbook for mobile devices, the maximum canvas size will be limited by the capacity of the device. Different devices will max out at different sizes, though the ultimate maximum canvas size is 100 megapixels.
Keep in mind that bigger may not be better - a 4k canvas on your mobile device will be a very large file, taking both storage on your device and impacting performance due to the RAM requirements of a large file.
What's the difference between ppi and dpi?
Let's start with what each stands for. PPI is pixels per inch, dpi is dots per inch. Both are used to describe the resolution of an image. PPI describes screen resolution (what you see on your monitor); whereas dpi describes print resolution (the number of dots of ink used when printing an image). In Sketchbook, the ratio of PPI to DPI is 1:1.
See below for some common document sizes.
A-series paper sizes
| Size | Width x Height (mm) | Width x Height (in) |
| A1 | 594 x 841 mm | 23.4 x 33.1 in |
| A2 | 420 x 594 mm | 16.5 x 23.4 in |
| A3 | 297 x 420 mm | 11.7 x 16.5 in |
| A4 | 210 x 297 mm | 8.3 x 11.7 in |
US Paper sizes
| Size | Width x Height (mm) | Width x Height (in) |
| Letter | 216 x 279 mm | 8.5 x 11.0 in |
| Legal | 216 x 356 mm | 8.5 x 14.0 in |
Common photo print sizes
| Print size | Image size for 300 dpi |
| 3 x 5 inches | 900 x 1500 pixels |
| 4 x 6 inches | 1200 x 1800 pixels |
| 5 x 7 inches | 1500 x 2100 pixels |
| 8 x 8 inches | 2400 x 2400 pixels |
| 8 x 10 inches | 2400 x 3000 pixels |
| 8.5 x 11 inches | 2550 x 3300 pixels |
| 9 x 16 inches | 2700 x 4800 pixels |
| 11 x 14 inches | 3300 x 4200 pixels |
| 11 x 16 inches | 3300 x 4800 pixels |
