Updating live: (X ÷ Y) × 100. Checking a test score or survey share? Same formula.
Updating live: ((end − start) ÷ |start|) × 100. Looking at investment growth instead? Use CAGR.
X% of Y: The portion of Y that equals X percent — commonly used for tips, taxes, and discounts.
X is what % of Y: Shows what fraction X represents out of Y as a percentage.
Percentage Change: The relative increase or decrease between two values, expressed as a percent.
Increase vs. Decrease: A positive change means growth; a negative change means decline.
Three tools on one page. "X% of Y" multiplies Y by X divided by 100. "X is what % of Y" divides X by Y and multiplies by 100. "Percentage Change" subtracts the starting value from the ending value, divides by the absolute starting value, and multiplies by 100. All three update live as you type — no rounding is applied until the displayed result.
Use the first calculator: Enter your tip percentage in X and the bill total in Y. For example, 20% of $50 gives you $10.
Percentage change is relative (comparing to the original value), while percentage points is absolute (simple subtraction). If a rate goes from 10% to 15%, that's a 5 percentage point change but a 50% percentage change.
Yes. If a value increases from $10 to $50, that's a 400% increase. There's no limit to percentage change.
If you know 20% of a number is 40, divide 40 by 0.20 to get 200. Use the second calculator in reverse: put the result in Y and the percentage in X, then solve for the missing value.
For percentage change, dividing by zero is undefined (you can't calculate a percentage change from zero). The calculator requires a non-zero starting value.
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.