What amount of MG of Vyvanse should I take if 30 mg of Ritalin ER works just fine for me?

Hi!
There really is no equivalency between dosages of these two medications because they are in different drug classes and work differently. Both are Central Nervous System stimulants but Ritalin is methylphenidate and Vyvanse is an amphetamine type drug. Both are controlled substances so only a doctor could prescribe a Vyvanse dose that's appropriate for you based on your medical history and response to the drug.
Regards, Wildcat