The total in B18 is the whole pie and the percentages in column C will be the slices. To calculate the percentage of a total in Excel execute the following steps. Enter the formula shown below.
The excel formula for percentage is Portion Days Total Days 100.
The formulas in Cells B1 and C1 copied to rows two to four is this. The math to determine a percentage is to divide the numerator the number on top of the fraction by the denominator the number on the bottom of the fraction then. You can explore it more with different examples and formulas. In column C we want to know the percentage that each month contributed to the total.