Question 1

How do I calculate a percentage of a number?

Accepted Answer

Multiply the number by the percentage expressed as a decimal. For example, 25% of 200 is 200 × 0.25 = 50. This calculator handles that instantly in its "what is X% of Y" mode.

Question 2

How do I find what percent one number is of another?

Accepted Answer

Divide the part by the whole and multiply by 100. If you scored 80 out of 100, that is (80 / 100) × 100 = 80%. The calculator computes this in its "X is what percent of Y" mode.

Question 3

What is percentage change and how is it calculated?

Accepted Answer

Percentage change measures how much a value moved relative to its starting point: ((New - Old) / Old) × 100. A positive result is an increase, a negative result is a decrease.

Question 4

What is the difference between percentage and percentage points?

Accepted Answer

A percentage is a fraction of 100. A percentage point is the arithmetic difference between two percentages. Moving from 10% to 15% is a rise of 5 percentage points but a 50% relative increase.

Question 5

How do I add or subtract a percentage?

Accepted Answer

Multiply the base by (1 + rate) to add, or (1 - rate) to subtract. Adding 15% to $100 gives $115; subtracting 15% from $100 gives $85. Use the change mode to see this in one step.

Percentage Calculator

How to Use the Percentage Calculator

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