Roll diameter formula
The requested label quantity is converted to machine-direction repeats based on labels across. The required web length is calculated from pitch, then roll geometry is solved for the outside diameter.
Repeats = ceil(label quantity ÷ labels across)
Web length = repeats × pitch + extra web
OD = √(Core OD² + 4 × thickness × web length ÷ π)
Web length = repeats × pitch + extra web
OD = √(Core OD² + 4 × thickness × web length ÷ π)
Check equipment limits
A mathematically valid roll may still be too large for a printer, rewinder, applicator or shipping specification. Compare the calculated OD with your equipment's maximum roll diameter and allow room for normal production variation.