JCalc

Percentage Calculator

Calculate percentages for any scenario: find X% of Y, what percent Y is of X, or percentage change. Free, instant results—no signup required.

%

Result

Result
30
Explanation
20% of 150 = 30.00

Percentage Formulas

Percent means 'per hundred.' To find X% of Y, convert X to a decimal (X/100) and multiply by Y. To find what percent Y is of X, divide Y by X and multiply by 100. For percentage change, compare the difference to the original value.

X% of Y = (X ÷ 100) × Y
Y is what % of X = (Y ÷ X) × 100
% Change = ((New - Old) ÷ Old) × 100
Example:

20% of 250 = 50. 40 is 20% of 200. A price change from $50 to $60 is a 20% increase.

How to Use the Percentage Calculator

Select the calculation type: "X% of Y" finds a percentage of a number; "Y is what % of X" finds what percentage one number is of another; "Percentage change" calculates increase or decrease from old to new value. Enter your numbers and see results immediately.

Example: Common Percentage Scenarios

Tip calculation: 18% of $45 = $8.10. Grade: 42 correct out of 50 = 84%. Price increase: $100 to $120 = 20% increase. Discount: 25% off $80 = $20 off, final price $60. Use our percentage calculator above for your own numbers. For investment returns, try our ROI calculator.

Frequently Asked Questions

How do I calculate X% of Y?

Multiply Y by (X/100). For example, 20% of 150 = (20/100) × 150 = 30. Use our 'X% of Y' mode: enter 20 and 150 to get 30.

How do I find what percent Y is of X?

Divide Y by X and multiply by 100. For example, 25 is what percent of 200? (25/200) × 100 = 12.5%. Use our 'Y is what % of X' mode: enter 25 and 200.

How do I calculate percentage increase or decrease?

Use the formula: ((New Value - Old Value) / Old Value) × 100. A positive result is an increase; negative is a decrease. Example: price goes from $80 to $100. ((100-80)/80) × 100 = 25% increase.

Can I use this for discounts and tax?

Yes! For a 15% discount on $80: use X% of Y with 15 and 80 = $12 off. For 'what percent' scenarios (e.g., tax rate), use Y is what % of X. Our calculator handles all common percentage cases.

Related Calculators

Measuring investment returns? Use our ROI calculator. Planning a loan? Try our loan calculator.