Percentage Calculator & Mental Math Hacks: What is X% of Y?
Percentages are a daily necessity for calculating sales tax, restaurant tips, retail discounts, interest rates, and investment returns.
The Secret Reversible Percentage Rule
One of the most powerful mental math secrets is: X% of Y is always equal to Y% of X.
For example, calculating 16% of 50 in your head might feel difficult. But by reversing it, 50% of 16 is obviously 8! Therefore, 16% of 50 is also 8.
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Calculate PercentageFrequently Asked Questions
How to calculate what percentage one number is of another?
Divide the part by the whole and multiply by 100. (Part ÷ Whole) × 100.
How to calculate percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100: [(New - Old) ÷ Old] × 100.