Percentage Formula Calculator
Easily solve percentage increase, decrease, differences, and fractions with step-by-step formula explanations and worked examples.
Also covers: percentage increase calculator with formula and steps · percentage difference solver · calculate percent of a number
Formula & How It Works
percentage = (part ÷ whole) × 100
- “Is what %” takes the first value as the part and the second as the whole: 15 of 80 is 18.75%.
- “% of” multiplies the number by the percentage divided by 100: 25% of 80 is 20.
- “Change” uses ((new − old) ÷ old) × 100, which reads 200 → 250 as +25%.
Step-by-Step Example
Two of the most common questions: what percentage 15 is of 80, and the change from 200 to 250.
- 1.Percentage of a whole
- 15 ÷ 80 × 100 = 18.75%
- 2.Percentage change
- (250 − 200) ÷ 200 × 100 = 25%
- 3.Reading it in reverse
- 25% of 80 = 80 × 25 ÷ 100 = 20
15 is 18.75% of 80, and 200 → 250 is a 25% increase.
Frequently asked questions
How do you calculate percentage increase between two numbers?
Subtract the starting value from the new value, divide by the starting value, then multiply by 100. Going from 200 to 250 is (250 − 200) ÷ 200 × 100 = 25% increase. A negative result means you have a decrease instead, so 250 → 200 is −20%.
What is the formula to find the percentage of a total?
Divide the part by the whole and multiply by 100. For example 15 out of 80 is 15 ÷ 80 × 100 = 18.75%. To go the other way and find a percentage of a number, multiply the number by the percentage divided by 100 — 25% of 80 is 20.
How is percentage difference different from percentage change?
Percentage change has a direction and always uses the original value as its base, so 200 → 250 is a 25% increase while 250 → 200 is a 20% decrease. Percentage difference compares two values with no starting point, using their average as the base, so it gives the same answer whichever way round you enter them.
About the Percentage Formula Calculator
Easily solve percentage increase, decrease, differences, and fractions with step-by-step formula explanations and worked examples.
It runs entirely in your browser — nothing you type is sent to a server — and the result updates as you edit the inputs. Estimates are for educational and informational purposes only; see ourdisclaimer.
Common searches
- percent
- percent change
- increase
- decrease
- of
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