Compound Percentage Change
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This calculator works out compound percentage change over multiple periods. It’s useful for repeated price rises, monthly growth rates, investment returns, inflation adjustments, and any situation where the percentage change applies again and again.
Compounding is different from adding the percentages. For example, increasing £100 by 10% for two periods is not £100 + 20% = £120. It’s £100 × 1.10 × 1.10 = £121.00. This page calculates the final value and also shows the total overall percentage change from the original value. If you only need a single-step change from old to new, use the Percentage Change calculator.
Formula: final = start × (1 + p/100)n.
Worked examples
Example 1: £100 +10% for 2 periods
Steps: 100×1.10² = 121
Result: £121.00 (21.00% total increase)
Example 2: £200 +3% for 12 months
Steps: 200×1.03¹²
Result: £253.85 (26.93% total increase)
Common questions
What does compound percentage mean?
It means the percentage change applies repeatedly to the updated value each period.
Why isn’t compounding the same as adding percentages?
Because each period’s change uses a new base value, so the effect stacks.
Can I use a negative percentage?
Yes. A negative rate models repeated decreases (e.g., depreciation).
What if periods is 0?
The final value equals the starting value because no changes are applied.