A weighted average is a calculation that assigns a different value to each number in a set, and then calculates the average of those values. The value of each number is determined by the weight assigned to it. To calculate a weighted average in Excel, you need to create a table with the weights in the first column and the numbers to be averaged in the second column. The sum of the weights in the table should be 1. To calculate the weighted average, simply enter the following formula into the cell where you want the result: =sum(B2:B10)/sum(B2:B10)*100, where B2:B10 is the range of cells containing the weights and numbers to be averaged.