Percentage and percentage change with examples

Choose the operation

“What is 20% of 150?” asks for part of a value. “How much did 150 increase to 180?” compares two values.

Percentage of a number

Use percentage × number ÷ 100: 20 × 150 ÷ 100 = 30. Select that operation in the percentage calculator. For a discount, 30 is the discount amount; subtract it from 150 for a final price of 120.

Percentage change

For a positive starting value, use (new − old) ÷ old × 100. Moving from 150 to 180 gives 20%; moving to 120 gives −20%. Enter the old value first. Moving from 120 back to 150 is a 25% increase because the starting point differs.

Percentage points

A rate rising from 10% to 12% rises by two percentage points, but its relative increase is 20%. State which comparison you mean.

Limits

A zero starting value makes this calculation undefined. For negative starting values, the tool divides by the absolute original value; check whether this definition fits your use case. Keep precision until final rounding.

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