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Percentage Change

Percentage change quantifies how much a value has increased or decreased relative to its starting point. It is one of the most frequently used calculations in business reporting, finance, and everyday life — yet it is easy to confuse with percentage points, percentage difference, and absolute change. Our calculator handles all four concepts and explains when to use each.

Percentage Change

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About the Percentage Change Calculator

Percentage change quantifies how much a value has increased or decreased relative to its starting point. It is one of the most frequently used calculations in business reporting, finance, and everyday life — yet it is easy to confuse with percentage points, percentage difference, and absolute change. Our calculator handles all four concepts and explains when to use each.

How to use it

  1. Enter the original (old) value and new value.
  2. See the percentage change, absolute change, and direction (increase/decrease).
  3. Switch to "percentage difference" mode for comparing two values without a clear baseline.
  4. Use the reverse calculator to find the original value from a known percentage change.

Formula & methodology

Percentage change = ((New − Old) / |Old|) × 100. Percentage difference = (|A − B| / ((A + B) / 2)) × 100. Finding new value: New = Old × (1 + rate/100). Finding original: Old = New / (1 + rate/100). Note: a 50% increase followed by a 50% decrease does NOT return to original.

Common use cases

  • Reporting sales growth quarter-over-quarter or year-over-year
  • Calculating discount: "30% off $80" → $80 × (1 − 0.30) = $56
  • Investment return: stock bought at $40, sold at $55 → 37.5% gain
  • Comparing economic indicators (GDP growth, inflation rate)
  • Salary negotiation: "10% raise from $75,000" → $82,500

Frequently asked questions

Percentage change is relative to the original value. Percentage points is an absolute difference between two percentages. Example: if interest rates go from 2% to 3%, that is a 1 percentage point increase but a 50% change (1/2 × 100). The distinction matters enormously in policy reporting.
Because each percentage is applied to a different base. $100 + 50% = $150. $150 − 50% = $75 (not $100). The sequence is asymmetric. To return to $100 from $150, you need a 33.3% decrease. This is why "average percentage change" in volatile investments can be misleading.

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