Math & Everyday
Percentage Calculator
The everyday percentage calculator. Find a percentage of a number, figure out what percentage one number is of another, or calculate the percent increase or decrease between two values.
Quick answer: To find X% of a number, multiply by X/100; to find what percent one number is of another, divide and multiply by 100; for percent change, divide the difference by the original.
Three of the most common percentage questions in one place. Percent change is positive for an increase and negative for a decrease, measured against the original value.
How it works
1. Identify the part and the whole
Most percentage questions reduce to a part and a whole. To find 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 x 100, or 25%.
2. Find a percentage of a number
To take a percentage of a value, convert the percent to a decimal and multiply. 15% of 80 is 0.15 x 80, which equals 12. This is the math behind tips, taxes, and discounts.
3. Calculate percent change
Percent change is the difference between two values divided by the original, times 100. Going from 50 to 65 is (65 - 50) / 50 x 100, a 30% increase. A negative result means a decrease. The calculator handles all three percentage modes.
Frequently asked questions
How do I find a percentage of a number?
Multiply the number by the percentage divided by 100. For example, 20% of 80 is 80 × 0.20 = 16.
How do I calculate percent change?
Subtract the old value from the new, divide by the old value, and multiply by 100. A negative result is a decrease.
What is X as a percentage of Y?
Divide X by Y and multiply by 100. For example, 30 out of 120 is 30 ÷ 120 × 100 = 25%.
How do I calculate what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 45 out of 180 is 45 / 180 x 100, which equals 25%. This answers questions like what percentage a score or portion represents.
How do I find the percentage of a number?
Convert the percentage to a decimal and multiply it by the number. To find 20% of 150, compute 0.20 x 150, which equals 30. Moving the percent's decimal two places left turns it into the multiplier.
How do I calculate percent increase or decrease?
Subtract the original value from the new value, divide by the original, and multiply by 100. From 80 to 100 is (100 - 80) / 80 x 100, a 25% increase; a negative result indicates a decrease. Always divide by the starting number, not the new one.
What is the difference between percentage points and percent?
A percentage point is the arithmetic difference between two percentages, while percent describes relative change. Going from 5% to 10% is a 5-percentage-point rise but a 100% increase. Mixing the two is a common source of misleading statistics.