A weighted average is where some of your scores or points count more than others. To calculate your average, take the first score and multiply it by the number of times it counts. For example, if you scored an A on a college course that was worth 3 credits, you would multiply that A, or 4 by the number of credits. The weight of this class would be 12. Then assume you scored a C (or 2) in a lab that counted as 5 credits. Your weight in this class would be 10. Add up the number of weights, in this case, the answer is 22. Divide that by the number of credits, or 8. Your weighted average would be 2.75 which equals a C.