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What Is Percentage Increase? Formula, Examples, and Common Uses

Understand percentage increase: the formula, how to calculate it step by step, and real-world examples in prices, salaries, and test scores. Includes common mistakes to avoid.

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What Percentage Increase Means

A percentage increase describes how much a value has grown relative to its original value, expressed as a percentage of that original.

Formula: Percentage Increase = ((New Value − Original Value) ÷ Original Value) × 100

It answers the question: "By what percentage did this value grow?"

Step-by-Step Calculation

Example 1: Price increase A product costs $80 and the new price is $100. - Change = $100 − $80 = $20 - Percentage Increase = ($20 ÷ $80) × 100 = 25% increase

Example 2: Salary raise Salary goes from $65,000 to $70,000. - Change = $70,000 − $65,000 = $5,000 - Percentage Increase = ($5,000 ÷ $65,000) × 100 = 7.69% increase

Example 3: Test score improvement Score improves from 72 to 89. - Change = 89 − 72 = 17 - Percentage Increase = (17 ÷ 72) × 100 = 23.6% increase

Common Mistakes

Mistake 1: Dividing by the new value instead of original Many people mistakenly calculate (change ÷ new value) × 100, which gives a different and incorrect result. - Wrong: ($20 ÷ $100) × 100 = 20% (this is the % of new value, not the increase) - Correct: ($20 ÷ $80) × 100 = 25%

Mistake 2: Confusing percentage increase with percentage points If a tax rate rises from 15% to 20%, the increase is: - 5 percentage points (absolute difference) - 33.3% increase in the tax rate (relative change: 5 ÷ 15 × 100)

These are different things. Financial and political contexts often exploit this ambiguity.

Reverse Calculation: Finding the Original Value

If you know the final value and percentage increase, you can find the original:

Original Value = New Value ÷ (1 + Percentage Increase/100)

Example: After a 20% increase, a product costs $120. What was the original price? - Original = $120 ÷ 1.20 = $100

Percentage Increase vs. Percentage Change

"Percentage change" is the general term; it can be positive (increase) or negative (decrease). "Percentage increase" specifically refers to upward changes.

When a value decreases, the formula gives a negative result — this is a percentage decrease, not a percentage increase.

Real-World Applications

  • Retail: "30% off" means a 30% decrease from original price
  • Finance: Investment returns expressed as percentage increase/decrease
  • Salary: Raises quoted as percentage of current salary
  • Inflation: CPI measures percentage increase in price basket over time
  • Population: Growth rate expressed as annual percentage increase

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Frequently Asked Questions

What is the formula for percentage increase?
Percentage Increase = ((New Value − Original Value) ÷ Original Value) × 100. Always divide the change by the ORIGINAL value, not the new value. Example: from 50 to 75 is a (25 ÷ 50) × 100 = 50% increase, not (25 ÷ 75) × 100 = 33.3%.
Is 100% increase the same as doubling?
Yes — a 100% increase means the value increased by an amount equal to its original value, which exactly doubles it. Going from 50 to 100 is a 100% increase. Going from 50 to 150 would be a 200% increase.
What is the difference between percentage increase and percentage points?
Percentage points measure the arithmetic difference between two percentages. Percentage increase measures the relative change. Example: interest rate rising from 2% to 3% is a 1 percentage point increase, but a 50% percentage increase (1 ÷ 2 × 100 = 50%). These are two different facts about the same change.
How do I find the original price after a percentage increase?
Divide the current price by (1 + percentage/100). After a 25% increase, if the price is $125: original = $125 ÷ 1.25 = $100. Don't subtract the percentage — that only works for simple numbers and won't give the right answer in most cases.

Last updated 7/28/2026