What percent is A of B?
is what % of
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What is X% of B?
% of
is
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Percent change (old → new)
to
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How to use the percentage calculator
Percentages come up constantly, yet it is easy to forget which number to divide by. This tool offers the three most common patterns, so you just type numbers and get the answer instantly.
The three patterns
① "What percent is A of B?" for completion rates and shares (30 is 25% of 120). ② "What is X% of B?" for sale prices and fees (25% of 120 = 30). ③ Percent change for year-over-year or price increases (800 → 1000 is +25%).
X% off or X% up
For "20% off 1000", use ② to get 20% of 1000 = 200, then 1000 − 200 = 800. Or enter old 1000 and new 800 in ③ to confirm −20%. For sale prices directly, the discount calculator is handy.
Frequently asked questions
How do I find what percent A is of B?+
Compute A / B × 100.
For example, 30 out of 120 is 30 / 120 × 100 = 25%.
For example, 30 out of 120 is 30 / 120 × 100 = 25%.
How is percent change calculated?+
Use (new value − old value) / old value × 100.
Positive is an increase, negative a decrease. It is undefined when the old value is zero.
Positive is an increase, negative a decrease. It is undefined when the old value is zero.
How do I find a value after X% up or down?+
X% increase is value × (1 + X/100); X% decrease is value × (1 − X/100).
You can also enter old and new values in the percent-change row to check the rate.
You can also enter old and new values in the percent-change row to check the rate.
What is the difference between a ratio and a percentage?+
A ratio expresses a part of the whole as 1 (e.g. 0.25); a percentage multiplies that by 100 (25%).
Percentage = ratio × 100.
Percentage = ratio × 100.
Are my inputs stored?+
No. All calculation happens in your browser, and the values you enter are never sent to or stored on a server.
Formulas
・What percent A is of B = A ÷ B × 100
・X% of B = B × X ÷ 100
・Percent change (%) = (new − old) ÷ old × 100
・Percentage = ratio × 100 (standard mathematical definition)
・What percent A is of B = A ÷ B × 100
・X% of B = B × X ÷ 100
・Percent change (%) = (new − old) ÷ old × 100
・Percentage = ratio × 100 (standard mathematical definition)
Please note
This site does not represent any organization and does not guarantee the accuracy of the results. Rounding may cause slight differences between the displayed and exact values. Use as a guide.
This site does not represent any organization and does not guarantee the accuracy of the results. Rounding may cause slight differences between the displayed and exact values. Use as a guide.