Sizing loads

Hi,

I have a question regarding maximum demand

If you have multiple three phase loads and a multiple single phase load how do you calculate the total power.

I know how to calculate the loads (kW) for both single and three phase loads but when you want to combine these for total load how do you represent a single phase load to add to the three phase load

Do you have to change everything to KVA then add together??
Is there another calculation I need to work out.


Thanks