Work out any percentage instantly — find a percent of a number,
figure out what percent one number is of another, or calculate a percentage
increase or decrease. Free, fast, and works on any device.
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What is% of?
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is what % of?
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Fromto
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How to calculate a percentage
A percentage is simply a fraction of 100. The word "percent" means
"per hundred", so 25% is the same as 25 out of 100, or 0.25. Almost every
percentage problem is one of three types, and this calculator solves all
three for you.
1. Finding a percentage of a number
This answers questions like "what is 20% of 150?" — useful for discounts,
tips, and tax. Convert the percent to a decimal and multiply:
This answers "30 is what percent of 120?" — useful for test scores,
progress, and comparisons. Divide the part by the whole, then multiply by 100:
Percent = (Part ÷ Whole) × 100
Example: 30 out of 120 → (30 ÷ 120) × 100 =
0.25 × 100 = 25%.
3. Percentage increase or decrease
This answers "what is the percentage change from 80 to 100?" — useful for
price changes, growth, and weight loss. Subtract, divide by the original,
multiply by 100:
Change % = ((New − Old) ÷ Old) × 100
Example: 80 → 100 gives ((100 − 80) ÷ 80) × 100 =
(20 ÷ 80) × 100 = +25% increase. A negative answer means a decrease.
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Quick percentage tips
10% of anything — just move the decimal point one place left.
10% of 240 is 24.
1% of anything — move the decimal two places left.
1% of 240 is 2.4.
Tips made easy — 15% tip = 10% plus half of that 10%.
Reverse a discount — if an item is 25% off and costs $60, the
original price was $60 ÷ 0.75 = $80.
Percentages flip — 8% of 50 equals 50% of 8. Both are 4.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 to turn it into a decimal,
then multiply by the number. For 20% of 150: 20 ÷ 100 = 0.20, and
0.20 × 150 = 30.
How do I work out what percent one number is of another?
Divide the smaller "part" by the total "whole" and
multiply the result by 100. For example, 30 out of 120 is
(30 ÷ 120) × 100 = 25%.
How do I calculate percentage increase or decrease?
Subtract the old value from the new value, divide by the
old value, then multiply by 100. A positive result is an increase, a
negative result is a decrease.
How do I calculate a percentage discount?
Multiply the price by the discount percent as a decimal
to get the amount off, then subtract it. A 25% discount on $80 is
0.25 × 80 = $20 off, leaving $60.
What is the percentage formula?
The core formula is Percentage = (Part ÷ Whole) × 100.
Rearranged, Part = (Percentage ÷ 100) × Whole, which lets you solve for
whichever value is missing.
