How do you calculate percentage change between two values?

• A. (Value2 − Value1) / Value1 × 100.
• B. (Value1 − Value2) / Value1 × 100.
• C. Value2 ÷ Value1.
• D. (Value2 − Value1) × 100.

Answer: (A)

Percentage change shows how much a value has changed relative to the starting value, expressed as a percentage. You calculate it by taking the difference between the new value and the starting value, dividing that difference by the starting value, and multiplying by 100. This makes the result positive when the value increases and negative when it decreases, and it ties the change to the original amount. For example, moving from 50 to 65 gives (65 − 50) / 50 × 100 = 30%.

The ratio Value2 ÷ Value1 is a relative size, not a percentage, so it isn’t in percent unless you subtract 1 and multiply by 100. Multiplying the difference by 100 without dividing by the starting value ignores the base amount, and reversing the subtraction would flip the sign, giving the wrong direction of change.