Percentage Change Calculator
This calculator finds the percentage change between any two values and tells you whether the change is positive (an increase) or negative (a decrease). Enter your old value and your new value to get an instant result with clear, step-by-step workings.
How It Works
Percentage change is a general way to express how much something has changed relative to its starting value. Unlike percentage increase or decrease, this calculator handles both directions and clearly labels the result.
The Formula
% Change = ((New − Old) ÷ Old) × 100
A positive result means the value has increased; a negative result means it has decreased. The sign tells you the direction of the change, and the number tells you the magnitude.
Difference from % Increase or Decrease
The percentage change formula is identical to the increase/decrease formula. The difference is that this calculator accepts both directions and labels the result accordingly, making it more flexible for general use.
Worked Examples
Example 1: Temperature changes from 20°C to 25°C
((25 − 20) ÷ 20) × 100 = (5 ÷ 20) × 100 = +25% (increase)
Example 2: Headcount falls from 120 to 96 employees
((96 − 120) ÷ 120) × 100 = (−24 ÷ 120) × 100 = −20% (decrease)
Example 3: Revenue changes from £50,000 to £62,500
((62500 − 50000) ÷ 50000) × 100 = (12500 ÷ 50000) × 100 = +25% (increase)
Example 4: Electricity bill drops from £180 to £144
((144 − 180) ÷ 180) × 100 = (−36 ÷ 180) × 100 = −20% (decrease)
Example 5: Product weight changes from 450g to 400g
((400 − 450) ÷ 450) × 100 = (−50 ÷ 450) × 100 ≈ −11.11% (decrease)
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