How to Calculate Percentage Increase and Decrease
Compare an old value to a new value correctly — and avoid the classic mistake of dividing by the wrong number.
3 min read
Step by step
- Subtract the old value from the new value to get the change.
- Divide the change by the OLD value, never the new one.
- Multiply by 100 to get a percentage.
- Example: 100 to 150 is (150 - 100) / 100 x 100 = 50% increase.
Key takeaway: Always divide the change by the original value.
Do it automatically
Percentages, increases, discounts and margins in six modes.
Open the Percentage Calculator