Counting how many selections/checkboxes were selected in field

I have a connection field that has a many to many connection, field #1. I would like to count how many choices were selected in field #1, into a new field, field #2. Is there an equation that I could use?

Hello,

May be I do not understand your question because as I understand it’s simple just use the count field and select that connection.

Thanks,
Sunny Singla