Excel Percentage Formulas: Change, Total and Markup
By Szabó Gergő · Updated
Excel percentages are decimal values displayed with percentage formatting. The correct formula depends on whether you need a share of a total, a rate of change, or an amount increased or reduced by a rate.
Syntax and arguments
=part/total or =(new_value-old_value)/old_value- part
- The amount represented as a share of the total.
- total
- The complete amount used as the denominator.
- old_value
- The baseline for a percentage-change calculation.
- new_value
- The updated value being compared with the baseline.
Percentage formulas examples
A category amount is B2 and the overall total is B10.
=B2/$B$10Locking B10 lets you copy the formula down; format results as Percentage.
Old revenue is B2 and new revenue is C2.
=IFERROR((C2-B2)/B2,"")The difference is divided by the old value, with a blank fallback when the old value is zero.
Price is B2 and discount percentage is C2.
=B2*(1-C2)Subtracting the rate from 1 gives the percentage of the original price that remains.
Common mistakes
Multiplying by 100 and using Percentage format
Do one or the other. Usually use the decimal formula and apply Percentage formatting.
Dividing change by the new value
Standard percentage change divides by the old or baseline value.
Baseline is zero
Define the desired business behavior and use IF or IFERROR to avoid #DIV/0!.
Percentage formulas FAQ
How does Excel store 20%?
Excel stores 20% as 0.2. Percentage formatting changes its display, not its underlying value.
How do I add 15% to a number?
Multiply the original value by 1+15%, for example =A2*(1+15%).
What is the difference between percentage change and percentage points?
Percentage change is relative to the old rate. Percentage points are the direct subtraction between two percentage rates.