Percentage Calculator — Percent Of, Percent Change & More

Percentage calculator.

Three everyday percentage questions, answered as you type.

Percent (%) of value Value out of total Change from to

The three calculations

Most "percentage" questions are one of three things. X% of Y just multiplies — 15% of 80 is 0.15 × 80 = 12. What percent is X of Y divides and scales — 30 out of 120 is 30 ÷ 120 × 100 = 25%. And percent change measures the difference relative to where you started: (new − old) ÷ old × 100, so 50 → 75 is a 50% increase. The change figure is the one people get wrong most often, because the denominator is always the original value, not the new one. For shopping math, the discount calculator and sales tax calculator apply these same formulas to prices.

Percentage points vs. percent

These two phrases mean different things, and mixing them up is the most common percentage error in news and reports. A percentage point is the plain arithmetic gap between two percentages; a percent change is that gap relative to the starting value. If a rate rises from 4% to 6%, it went up 2 percentage points — but it rose 50% (2 ÷ 4 × 100), because the increase is measured against the original 4%. Saying it "rose 2%" would be wrong. The same trap appears with margins and interest rates: always ask whether a figure is an absolute point difference or a proportional change before you compare it.

FAQ

How do I calculate what percent one number is of another?

Divide the part by the whole and multiply by 100. For example, 30 out of 120 is 30 ÷ 120 = 0.25, which is 25%.

How do I work out percent increase or decrease?

Subtract the old value from the new value, divide by the old value, then multiply by 100. Going from 50 to 75 is (75 − 50) ÷ 50 × 100 = 50% increase; a negative result means a decrease.

How do I add or remove a percentage from a number?

To add, multiply by 1 plus the percentage as a decimal: adding 20% to 50 is 50 × 1.20 = 60. To remove it, divide by that same factor: a price of 60 that already includes 20% is 60 ÷ 1.20 = 50. Dividing, not subtracting 20%, is what backs out the original amount correctly.

What is a percentage of a percentage?

Convert each percentage to a decimal and multiply. For example, 50% of 20% is 0.50 × 0.20 = 0.10, which is 10%. This comes up with stacked discounts: an extra 10% off an item already reduced 30% leaves 0.90 × 0.70 = 0.63, so you pay 63% of the original — a 37% total discount, not 40%.

Percentage calculator.

The three calculations

Percentage points vs. percent

FAQ

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