Percentage Calculator
Four percentage calculators in one: find a percent of a number, calculate what percent one number is of another, and find percentage change or difference.
What is X% of Y?
Enter values to see result.
Result
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Formulas
All percentage formulas.
X% of Y
result = Y × (X ÷ 100)
25% of 200 = 200 × 0.25 = 50
X is what % of Y?
result = (X ÷ Y) × 100
45 is what % of 180? → (45 ÷ 180) × 100 = 25%
% change (old → new)
result = ((new − old) ÷ |old|) × 100
80 → 100: ((100 − 80) ÷ 80) × 100 = +25%
% difference
result = (|A − B| ÷ ((A + B) ÷ 2)) × 100
40 vs 50: (10 ÷ 45) × 100 ≈ 22.22%
FAQ
Frequently asked questions.
What is a percentage?
A percentage is a number expressed as a fraction of 100. The word comes from Latin "per centum" meaning "by the hundred." So 45% means 45 out of every 100, or 0.45 as a decimal.
How do I calculate percentage increase or decrease?
Subtract the old value from the new value, divide by the old value, then multiply by 100. Example: price goes from $80 to $100 → (100 − 80) ÷ 80 × 100 = 25% increase.
What is the difference between percentage points and percent?
Percentage points are an absolute difference. If a rate goes from 5% to 8%, that is a 3 percentage-point increase — but a 60% relative increase. Confusing the two is a common mistake in news reporting.
How do I find the original price after a discount?
If you know the final price and the discount percentage, use: original = final ÷ (1 − discount%). Example: $75 after a 25% discount → 75 ÷ 0.75 = $100 original.
How do I calculate percentage of a total?
Divide the part by the whole, then multiply by 100. Example: 45 out of 180 students passed → 45 ÷ 180 × 100 = 25%.
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