Looking for a percentage calculator increase decrease of a number? This free tool gives you percent of a number, percent change and what percent one number is of another. Just enter your numbers and press Calculate — results are instant.
Percent means 'out of a hundred', and this calculator does the three jobs people actually need: what is X percent of Y, what percent X is of Y, and the percent change from X to Y. Percent of a number is the percent divided by 100 times the number. Percent change is the difference divided by the starting number, times 100 — positive for an increase, negative for a decrease.
Example: What is 15% of 200?
Result: 30.0000
First, what is X% of Y — a straight percentage of a number. Second, X is what percent of Y — the share one number is of another. Third, percent change — how much a number rose or fell from one value to another.
Take the difference between the new and old values, divide by the old value, and multiply by 100. A rise from 200 to 250 is (50 ÷ 200) × 100 = 25%.
Divide the new value by one plus the percent as a decimal. If a price rose 10% to $110, the original was $110 ÷ 1.10 = $100.