Excel percentage formulas can get you through problems large and small every day—from determining sales tax (and tips) to calculating increases and decreases. We’ll walk through several examples below: turning fractions to percentages; backing sales tax out of totals; percentage of total; percentage increase or decrease; percentage of completion; and percent ranking (percentile).
Turning fractions to percentages
Percentages are a portion (or fraction) of 100. 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 multiply the answer by 100. For example, the fraction 6/12 turns into a decimal like this: 6 divided by 12 (which equals 0.5) times 100 equals 50 percent.