Percentage Decrease Calculator

Calculate the percentage decline from a starting value to a final value, or decrease a base number by a specific percentage.

1Decline from Value A to Value B

2Decrease a Number by X%

The Percentage Decrease Formula

Percentage decrease calculates the relative drop or reduction of an amount. Use the following mathematical formula:

Percentage Decrease = ((Original Value - New Value) / Original Value) × 100

How to Calculate Step-by-Step

  1. Find the Difference: Subtract the final value (New Value) from the starting value (Original Value). For example, if a product is marked down from $120 to $90, the discount is 120 - 90 = $30.
  2. Divide by the Original: Divide that absolute difference by the original value. In our example: 30 / 120 = 0.25.
  3. Convert to Percentage: Multiply the decimal result by 100. So, 0.25 × 100 = 25%.

Real-World Applications

Percentage decrease helps individuals and businesses measure price drops, physical losses, and value declines:

CategoryReal-World ExampleWhy it Matters
Retail MarkdownA winter jacket priced at $80 is marked down to $60.Calculates a 25% discount rate on the product.
Asset DepreciationA company laptop value drops from $1,000 to $700.Measures a 30% loss in standard hardware value.
Weight LossA health client weight drops from 180 lbs to 162 lbs.Tracks a 10% weight loss progress.
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How to Calculate in Excel

Use the following formula in Excel or Google Sheets to determine percentage decrease automatically:

=(A2-B2)/A2
  • A2: Original value
  • B2: New value
  • Format: Format the cell using the % symbol.