Percentage Increase or Decrease Calculator
Number × (1 ± Percentage ÷ 100)200 × (1 + 15 ÷ 100) = 230
Free online tool
Percentage Increase or Decrease Calculator
Apply a percentage increase or decrease to a starting value and see the final amount instantly.
Instant calculation
Increase or decrease a number by a percentage
Apply a percentage increase or decrease to a value.
Your result
Calculation
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The formula
How this calculation works
For an increase, add the decimal percentage to 1. For a decrease, subtract it from 1. Multiply the starting number by that factor.
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Worked examples
Each example follows the same formula used by the calculator above.
Increase 200 by 15%
200 × (1 + 15 ÷ 100) = 230Answer: 230Decrease 200 by 15%
200 × (1 − 15 ÷ 100) = 170Answer: 170Increase 80 by 125%
80 × (1 + 125 ÷ 100) = 180Answer: 180Common questions
Questions about this calculation
How do I increase a number by a percentage?
Multiply the number by 1 plus the percentage written as a decimal. Increasing 200 by 15% means 200 × 1.15 = 230.
How do I decrease a number by a percentage?
Multiply the number by 1 minus the percentage written as a decimal. Decreasing 200 by 15% means 200 × 0.85 = 170.
Can I reverse a percentage increase by subtracting the same percentage?
Usually not. Increasing 100 by 20% gives 120, while decreasing 120 by 20% gives 96. The second percentage uses a different base.
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