Percentage Increase
$$\text{Percentage Increase} = \frac{\text{New} - \text{Old}}{\text{Old}} \times 100$$
What is Percentage Increase?
A percentage increase is a special case of percentage change where the new value is strictly greater than the original value. It quantifies growth relative to the starting point: $$\text{Percentage Increase} = \frac{\text{New} - \text{Old}}{\text{Old}} \times 100$$ The result is always positive. It tells you not just that something grew, but how large that growth was relative to where it started.
The choice of base — the original value — is what makes percentage increase a relative measure rather than an absolute one. A $10 increase on a $20 item (50% increase) communicates something very different from a $10 increase on a $1,000 item (1% increase), even though the absolute gain is identical.
Percentage increases compound multiplicatively. If a value increases by 20% and then by 30%, the combined effect is not 50% but 56%, because the second increase applies to the already-enlarged base: 1.20 × 1.30 = 1.56. For small percentages the difference is negligible, but for large percentages or long time horizons the compounding effect becomes significant.
When to use Percentage Increase
Use percentage increase when reporting growth, gains, or improvements where the original (lower) value is the natural reference point. Use it when communicating with a non-technical audience who needs context for absolute changes. When comparing growth across different-sized bases, percentage increase is the fair metric.
Worked examples
| Original value | New value | Absolute increase | Percentage increase |
|---|---|---|---|
| $500 | $600 | $100 | 20.00% |
| 2,000 users | 2,700 users | 700 users | 35.00% |
| €1,200 salary | €1,500 salary | €300 | 25.00% |
| 15 kg | 18 kg | 3 kg | 20.00% |
Common pitfalls
A 50% increase followed by a 50% decrease does not return to the original value — it leaves you at 75% of the starting point. Reversing a percentage increase always requires a larger percentage decrease: to reverse a 25% increase you need a 20% decrease (not 25%), because the base has changed.
Frequently asked questions
How do I reverse a percentage increase?
To find the percentage decrease needed to return to the original value after a P% increase, use: Decrease% = P / (100 + P) × 100. After a 25% increase, you need a 20% decrease. After a 100% increase (doubling), you need a 50% decrease. The reversal percentage is always smaller than the original increase.
What does a 100% increase mean?
A 100% increase means the value has doubled. The new value equals the original plus 100% of it: New = Old + Old = 2 × Old. A 200% increase means the value has tripled. Note that "increase by 200%" and "increase to 200%" mean different things — the latter means the value doubled.
Is percentage increase the same as a growth rate?
Yes, when calculated over a single period. A period-over-period percentage increase is a simple growth rate. When growth compounds over multiple periods, a compound annual growth rate (CAGR) is more appropriate, as it accounts for the multiplicative nature of sequential percentage increases.