CalcWhenPercentage Calculator
20% of 150 is 30 — the discount arithmetic behind every sale tag: a $150 item at 20% off drops by $30, to $120.
How it works
Percentages confuse because one word covers three different questions, so this tool names them plainly and solves whichever you pick: the part (what is 20% of 150), the rate (30 is what percent of 200), and the share (45 as a percentage of 60). Tips, discounts, tax, grades and survey results are all one of these three in costume.
For change over time — prices rising, scores improving — the percentage change calculator next door is the right tool; it is linked below and in the panel's family.
The method
What-is: result = X ÷ 100 × Y. What-percent: result = X ÷ Y × 100. Percent-of: result = X ÷ Y × 100 expressed as a share with its decimal form. Division by zero is reported, never fudged.
Frequently asked questions
How do I work out a 20% discount quickly?
Use “what is X% of Y” with X=20 and Y=the price — that is the amount off. Subtract it from the price for the sale price (or multiply the price by 0.8 in one step).
What percent is 45 out of 60?
75% — pick the second question with X=45, Y=60. Grades, test scores and completion rates are all this question.
Why is a 50% loss not undone by a 50% gain?
Because the base changes: 100 falling 50% becomes 50, and 50% of 50 is only 25, landing at 75. Percentage change always rides on the current value — the change calculator shows this plainly.