Units is a Sketch plugin for working with print units (inch, cm, mm) in Sketch's pixel world.
- Calculates the print unit value from the pixel value for width and heights and back
- Resizes one or more layers based on pixel unit values
- Download the plugin zip file from the releases page and extract the archive
- Double click on the de.dieploegers.sketchplugin file
Use the settings dialog to set up your desired unit and the dpi value (see below).
Then select a layer and use the resize command to either display the print unit value for its current size or resize it to a new value.
The DPI value (Dots Per Inch) is the main factor for converting pixels to print units and back.
If you plan to export your design as a vector file (e.g. PDF) you should set it to 72, because that's Sketch's default value.
On the other hand, if you plan to export to an image file, you can basically set this value to what you like, but for print it's usually 300.