How Much Motor Oil Do I Need To Refill This Lawn Mower?

I am fully changing the old motor oil in my CRAFTSMAN Rotary Lawn mower.
This 625-series, Briggs & Stratton motor turns a 22 inch blade to a side-discharge.
I need to know how much (I am using 30 weight) motor oil I need to buy to fully refill this motor after I drain it.
Thanks for knowledgeable replies.