Percentage Formula Generator for Excel
Percent of, percent change, increase and decrease, with the exact Excel formula.
15% of 80 = 12.00
=A2/100*B2The five percentage formulas
| Question | Formula | Example |
|---|---|---|
| What is 15% of 80? | =A2/100*B2 |
12 |
| 12 is what percent of 80? | =A2/B2, formatted as % |
15% |
| Change from 80 to 100 | =(B2-A2)/ABS(A2), formatted as % |
25% |
| Increase 80 by 10% | =A2*(1+B2/100) |
88 |
| Decrease 80 by 10% | =A2*(1-B2/100) |
72 |
Percent format and the 100 problem
Excel stores 15% as 0.15. If a cell already holds a percentage such as 15% (not the number 15), drop the /100: =A2*B2. If a result shows 0.25 where you expected 25%, apply Percentage format from Home > Number rather than multiplying by 100.
Why ABS in percent change
Dividing by ABS(A2) keeps the sign meaningful when the starting value is negative: a loss shrinking from -50 to -25 shows as a 50% improvement, not a 50% fall. If the starting value is zero, percent change is undefined and Excel returns #DIV/0!.
Sources: Function behaviour: Microsoft Support function reference. Results checked against worked examples, and generated formulas evaluated in the open-source HyperFormula engine. Method & sources