Hi Joshet, maybe if you clarified what kind of refrigerant you needed to calculate the capillary, you could have been given some more specific information.
As other members of the group suggested, in the downloads section there is a lot of info about capillaries.
I'm going to try to help you and I'm going to attach some tables so you can calculate the capillary tube selection according to compressor groups. And a pdf where it is explained and detailed how to make the necessary calculations.
CAPILLARS FOR R134a

CAPILLARS FOR R404a

CAPILLARS FOR R22

Here I attached a file so you can understand the function of capillaries and so you know how to calculate necessary. I hope I have helped and contributed to the solution to your problem. Regards...
Seleccion_de_capilares.pdf [75.93kb]