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%Percentage Calculator
① Percent change from A to B
② A is what percent of B?
③ What is A% of B?
④ Price after discount or markup
Percentage formulas
- Percent change = (B − A) ÷ A × 100
- A as a percent of B = A ÷ B × 100
- A% of B = A × B ÷ 100
- Sale price = price × (1 − percent ÷ 100); marked-up price = price × (1 + percent ÷ 100)
Frequently asked questions
How do I calculate percent increase?
Percent change = (new − old) ÷ old × 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = 25% increase.
If something goes up 20% and then down 20%, is it back where it started?
No. 100 up 20% is 120; 120 down 20% is 96. The second percentage is taken from a bigger base.
What is the difference between percent and percentage points?
Percentage points are the plain difference between two percentages. A rate rising from 4% to 5% is up 1 percentage point, which is a 25% increase.
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Last reviewed: 2026-10-17