Percentage Calculator
Solve all types of percentage problems — find %, what % of X is Y, and percentage change.
The Formula
Result = Y × (X / 100)
X is what % of Y:
% = (X / Y) × 100
% change from A to B:
Change = ((B − A) / A) × 100
= 240 × 0.35 = $84
17 is what % of 68?
= (17/68) × 100 = 25%
$80 → $96: change = (16/80) × 100 = +20%
Three Common Percentage Problems
1. What is X% of Y? Multiply Y by X/100. Example: What is 20% of 350? → 350 × 0.20 = 70.
2. X is what % of Y? Divide X by Y and multiply by 100. Example: 50 is what % of 200? → 50/200 × 100 = 25%.
3. Percentage change. (New − Old) / Old × 100. Example: From 100 to 130 = (130−100)/100 × 100 = 30% increase.
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage expressed as a decimal (divide the percentage by 100). 20% of 150 = 150 x 0.20 = 30. A quick mental shortcut: 10% of any number is just move the decimal one place left. Then scale: 20% is double the 10% figure, 5% is half, 15% is the 10% plus the 5%, and so on.
What is percentage change?
Percentage change = ((New Value - Old Value) / Old Value) x 100. A positive result is an increase, negative is a decrease. A stock going from $40 to $50 increased by ($50 - $40) / $40 x 100 = 25%. The same stock falling from $50 to $40 decreased by ($40 - $50) / $50 x 100 = -20%. Note the starting value in the denominator changes, which is why the percentages are not equal.
How do I calculate a percentage increase from one number to another?
Subtract the original from the new value, divide by the original, then multiply by 100. From 60 to 75: (75 - 60) / 60 x 100 = 15/60 x 100 = 25% increase. To quickly check: add 25% of 60 (which is 15) back to 60, and you get 75.
What is the difference between percent and percentage point?
Percent is a relative measure. Percentage point is an absolute difference between two percentages. If a tax rate rises from 10% to 12%, it rose by 2 percentage points but by 20% relative to the original rate. Both statements are technically correct but describe different things. Financial and political reporting often conflates these, so it pays to read carefully.
How do I work backwards from a percentage to find the original?
Divide the final amount by (1 + the percentage as a decimal) for increases, or by (1 - the percentage) for decreases. If an item costs $130 after a 30% markup, the original price was $130 / 1.30 = $100. If a sale price is $85 after a 15% discount, the original was $85 / 0.85 = $100. This reverse calculation is useful for tax-inclusive prices and discounted items.