Free Percentage Calculator
Three percentage calculators in one — results appear as you type.
What is X% of a number?
X is what percent of Y?
Percent increase / decrease
"Percentage points" and "percent" aren't the same thing
This mix-up shows up constantly in news headlines and data reporting. If a survey result moves from 40% to 50%, that's a 10 percentage-point increase — a simple subtraction of the two percentages. But expressed as a relative change, it's actually a 25% increase, since 10 is 25% of the original 40 — exactly what the third calculator above computes. Both descriptions are correct, but they answer different questions: percentage points describe the raw gap between two percentages, while "percent change" describes how large that gap is relative to the starting value. Mixing them up — especially in interest rates, tax rates, or survey results — is one of the most common statistics errors in everyday reporting.
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 15% of 200 is 200 × 15 ÷ 100 = 30. The first calculator above does this instantly.
How do I work out a percent increase?
Subtract the old value from the new, divide by the old value, then multiply by 100. Going from 80 to 100: (100 − 80) ÷ 80 × 100 = 25% increase. A negative result means a decrease.
Why is a 50% increase not undone by a 50% decrease?
Because the percentage applies to a different base each time. 100 increased 50% is 150; 150 decreased 50% is 75, not 100. The bigger the change, the bigger this asymmetry.
What's the difference between "percentage points" and "percent"?
Going from a 40% rate to a 50% rate is a 10 percentage-point increase (a simple subtraction), but it's a 25% relative increase (10 is 25% of 40). Both are correct descriptions of the same change — they just answer different questions, and mixing them up is a common source of confusion in news and financial reporting.
How do I add a percentage to a price (like tax)?
Multiply by 1 plus the rate: adding 8% tax to $50 is 50 × 1.08 = $54. For discounts, multiply by 1 minus the rate. Our tip calculator handles restaurant math directly.