Percent of versus percent off
“15% of 200” is 30. “15% off 200” is 170. The third mode (X is Y% of what) solves for the original. Pick the question that matches the sentence you are trying to finish.
Your numbers
Percentage
Common percent operations and discounts. Each stays a separate calculation.%
Result
30How we got this
- Operation15% of 200
- Result30
What we assumed
- Percent of: (percent ÷ 100) × base.
- What percent: part ÷ whole × 100. A zero whole is rejected.
- Percent of what: part ÷ (percent ÷ 100). A zero percent is rejected.
- Percent off: discount cannot exceed 100%.
Technical details
Method percentage-v1.0.0Data Manual inputs / fixed rules
Guide
Three percent questions, exactly
What is X% of Y, X is what percent of Y, and X is Y% of what. Division by zero is rejected. This is not a mortgage rate and not a tax bracket.
Questions about this calculator
What is 15 percent of 200?
30, using the first mode. A sale price of 15% off 200 is a different question; use the wording on the page that matches “off.”
Terms used here
- Percent
- A ratio times 100. This page does not add tax or round to currency unless the display does.
Practical tips
- For a price change from old to new, the percent-change calculator is the clearer tool.
Limits and caveats
- Exact arithmetic for the mode you picked. Not financial advice.
Results are for information. They are not legal, tax, medical, or financial advice. How the math is maintained · Report a wrong figure.
Engine notes
Rounding, versioning, and omissions that sit beside the guide rather than repeating it.
- X% of Y. Result = (X ÷ 100) × Y. Example: 15% of 200 is 30.
- X is what percent of Y. Result = (X ÷ Y) × 100. A zero baseline is rejected instead of returning Infinity.
- X is Y% of what. Result = X ÷ (Y ÷ 100). A zero percent cannot solve for the missing base.