Percentage Decrease Calculator South Africa


A percentage decrease measures how much a value has reduced relative to its original amount, expressed as a percentage.

Calculating this involves subtracting the final value from the original value, dividing the result by the original value, and then multiplying by 100 to get a percentage.

This calculation helps in understanding the extent of the reduction in various contexts, like sales, population, or other quantities.

How to Calculate Percentage Decrease

To calculate the percentage decrease in a way that’s easy to understand, follow these steps:

Identify the Original Value: This is the starting point or the initial amount before any decrease. For example, if you’re calculating the decrease in sales, this would be the sales number before the decrease.

Identify the New Value: This is the amount after the decrease. Continuing the sales example, this would be the sales figure after noticing a drop.

Subtract the New Value from the Original Value: This calculation gives you the absolute decrease in value. In mathematical terms: Decrease = Original Value - New Value.

Divide the Decrease by the Original Value: This step converts the absolute decrease into a relative measure. It shows how large the decrease is in relation to the original value. The formula is: Relative Decrease = Decrease / Original Value.

Convert to Percentage: To make this relative decrease a percentage, multiply it by 100. The formula is: Percentage Decrease = (Relative Decrease) x 100.

Interpret the Result: The final number you get is the percentage decrease. It tells you by what percentage the original value has decreased.


Imagine a store’s weekly sales dropped from $500 to $400. Here’s how you’d calculate the percentage decrease:

  1. Original Value (OV): R500
  2. New Value (NV): R400
  3. Calculate Decrease: R500 (OV) – $400 (NV) = $100
  4. Relative Decrease: R100 / R500 = 0.2
  5. Percentage Decrease: 0.2 x 100 = 20%

This result means that the store’s sales decreased by 20% from the original sales figure.