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Find a percentage of a number, work out what percent one number is of another, calculate a percentage increase or decrease, or average several percentages — instantly.
Enter each percentage on its own line, then average them.
A percentage calculator online free tool like this one works out any percentage problem instantly — no app to install, no account, no cost. A percentage itself is a way of expressing a number as a fraction of 100. The word comes from the Latin per centum, meaning "by the hundred." When you say something is "20%," you mean 20 out of every 100 — the same as the fraction 20/100 or the decimal 0.2.
Percentages let you compare quantities of different sizes on a common scale. Whether you're calculating a discount at checkout, working out a test grade percentage, tracking sales growth, or comparing a win percentage across a season, percentages turn raw numbers into something easy to compare.
Most people search "how to calculate percentage on a calculator" expecting one formula, but the right one depends on what you already know. This tool covers all three common cases plus averaging — pick the tab above that matches your question.
To average several percentages, add them together and divide by how many values you have — the same way you'd average any set of numbers.
This simple average only holds up when each percentage is based on the same size group. If the underlying totals differ — say, three test scores out of different numbers of questions — a weighted average is more accurate than a plain average.
Divide the part by the whole, then multiply by 100. For example, to find what percentage 30 is of 200: (30 ÷ 200) × 100 = 15%.
Multiply the number by the percentage, then divide by 100. For example, 20% of 150 is (150 × 20) ÷ 100 = 30.
Subtract the original value from the new value, divide by the original value, then multiply by 100. A positive result is a percentage increase; a negative result is a percentage decrease.
Add up all the percentages, then divide by how many there are — the same way you'd average any set of numbers. For example, the average of 80%, 90%, and 70% is (80+90+70)/3 = 80%. This simple average only works correctly when each percentage is based on the same-size group; otherwise a weighted average is needed.
On most calculators, typing a number, an operator (+ or -), a second number, then the % key applies that percentage to the first number automatically. For example, 200 + 10% returns 220, because it adds 10% of 200 to 200. Used alone after a number, % simply converts it to a decimal, so 50% becomes 0.5.
A percentage point is the arithmetic difference between two percentages. If a rate moves from 20% to 25%, that's a rise of 5 percentage points — but a 25% relative increase in the rate itself.