Overall GPA for Transfer Student

I transferred schools after 1 year of undergrad and have a question about how medical schools will calculate my overall GPA. Both schools had different credit systems as well as grading systems.

School 1: 1.0 credit/class with traditional (A,A-,B+,B…) scale- max credits/semester was 4.0

School 2: Various credits/class with modified (A,AB,B,BC…) scale- max credits/semester was 18.0

All of my 1.0 credit classes from my 1st school transferred over to my 2nd school as 4.0 credits/class.

What I’m wondering is how to calculate my overall GPA with all this factoring in. I understand the basic math of calculating a GPA, I just need help with the approach med schools will take in calculating it.

First thought is that they will simply use 4.0 credits/class instead of 1.0 for my 1st school’s courses. I’m just unsure if this is the correct way to do it since the 2 grading scales of the schools differ as well.

I appreciate the help.