Percentage Calculator
20% of 150 = 30
30 is 20% of 150
From 50 to 75 = +50% increase
X% of Y, X is what % of Y, and percentage increase/decrease | 100% Private
X% of Y, X is what % of Y, and percentage increase/decrease — all in one tool.
No submit button — results recalculate instantly as you edit any field.
Clearly labeled as an increase or decrease, with the correct + or − sign.
Clear error messages for empty fields or division by zero — never a crash.
All math runs locally in your browser. Nothing is ever uploaded.
Switch between calculation modes instantly with a single click.
Percentages show up everywhere — discounts, tips, exam scores, growth metrics, and financial reports. UtilityX's Percentage Calculator covers the three calculations people need most often, with live results and clear labeling so you always know exactly what was computed.
X% of Y = (X ÷ 100) × Y. X is what % of Y = (X ÷ Y) × 100. Percentage change from X to Y = ((Y − X) ÷ X) × 100, where a positive result is an increase and a negative result is a decrease.
20% of 150 is 30. Turning that around, 30 is 20% of 150. And if a value grows from 50 to 75, that's a +50% increase, since (75 − 50) ÷ 50 × 100 = 50%.
Multiply Y by X and divide by 100. For example, 20% of 150 is (20 × 150) / 100 = 30. Use the "X% of Y" tab and enter both values to see the live result.
Divide X by Y and multiply by 100. For example, 30 is what percent of 150? (30 / 150) × 100 = 20%. Use the "X is what % of Y" tab for this calculation.
Subtract the original value from the new value, divide by the original value, then multiply by 100: ((New − Old) / Old) × 100. A positive result is an increase; a negative result is a decrease. For example, from 50 to 75 is a +50% increase.
Yes, all three calculators accept negative numbers and decimals. The tool will show a clear error message instead of crashing if a required field is empty or a division by zero would occur.