Percentage Calculator
Find a percentage of a number, work out what percent one value is of another, or calculate percentage increase, decrease, and change — instantly.
Related calculators
What is a percentage?
A percentage is simply a way of expressing a number as a fraction of 100. When you say “20%,” you mean 20 out of every 100 — so 20% of 150 means taking 20 parts out of every 100 parts of 150. Percentages make it easy to compare proportions, track changes over time, and work with discounts, taxes, interest, and statistics.
How to calculate a percentage
The basic percentage formula tells you what fraction one number is of another, expressed out of 100:
Percentage = (Part ÷ Whole) × 100To find a percentage of a number, rearrange the formula: multiply the number by the percentage, then divide by 100.
X% of Y = (X ÷ 100) × YPercentage increase formula
Percentage increase = ((New − Original) ÷ Original) × 100Use this when a value has gone up and you want to know by what percentage.
Percentage decrease formula
Percentage decrease = ((Original − New) ÷ Original) × 100Use this when a value has gone down.
Percentage change vs. percentage increase/decrease
Percentage change is the signed version of the same calculation: ((New − Original) ÷ Original) × 100. A positive result means an increase, a negative result means a decrease. “Percentage increase” and “percentage decrease” describe that same value with a direction word instead of a sign — that’s what the “Increase / decrease” tab above shows.
Worked examples
- 20% of 150: (20 ÷ 100) × 150 = 30
- 30 is what % of 150? (30 ÷ 150) × 100 = 20%
- 150 to 180: ((180 − 150) ÷ 150) × 100 = 20% increase
- 150 to 120: ((120 − 150) ÷ 150) × 100 = −20%, i.e. a 20% decrease
- A value dropping from 80 to 60: ((60 − 80) ÷ 80) × 100 = 25% decrease
Frequently asked questions
How do I calculate a percentage?
Divide the part by the whole, then multiply by 100: Percentage = (Part ÷ Whole) × 100. For example, 30 out of 150 is (30 ÷ 150) × 100 = 20%.
How do I calculate percentage increase?
Subtract the original value from the new value, divide by the original value, then multiply by 100: ((New − Original) ÷ Original) × 100. Going from 150 to 180 is a 20% increase.
How do I calculate percentage decrease?
Subtract the new value from the original value, divide by the original value, then multiply by 100: ((Original − New) ÷ Original) × 100. Going from 150 to 120 is a 20% decrease.
How do I calculate percentage change?
Use ((New − Original) ÷ Original) × 100. The result is positive for an increase and negative for a decrease, so it captures both directions in a single signed number.
What is the difference between percentage change and percentage increase or decrease?
They’re the same calculation. Percentage change gives a signed result (positive or negative), while percentage increase and percentage decrease describe that same result using a direction word and a positive number instead of a sign.