Percentage Increase Calculator
Find the percentage increase or decrease from one value to another.
Enter values above to calculate
The Formula
% increase = ((New − Old) ÷ Old) × 100
⚠️ Always divide by the original value — dividing by the new value is the most common mistake.
Step-by-Step (80 → 100)
1 Difference: 100 − 80 = 20
2 Divide by original: 20 ÷ 80 = 0.25
3 Multiply by 100: 0.25 × 100 = 25%
4 Verify: 80 × 1.25 = 100 ✓
Frequently Asked Questions
What is the percentage increase formula?
Percentage increase = ((New − Old) ÷ Old) × 100.
What if my result is negative?
A negative result means the value decreased. Going from 100 to 80 gives −20%.
Is a 100% increase the same as doubling?
Yes. A 100% increase means the value grew by its full original amount — so it doubled.
How is percentage increase different from percentage points?
If a rate rises from 2% to 3%, that is 1 percentage point but a 50% relative increase.