Percentage Change Calculator
Instantly calculate the percentage increase or decrease between two values. Get the formula, step-by-step breakdown, and real-world examples — all in one place.
Percentage Change Formula
The standard formula uses the absolute value of the original number in the denominator, which allows it to correctly handle negative starting values too.
Percentage Increase
When V₂ > V₁, the result is positive — the value has grown.
- Sign of result: positive (+)
- Formula result > 0 means an increase
- Example: 100 → 130 = +30%
Percentage Decrease
When V₂ < V₁, the result is negative — the value has dropped.
- Sign of result: negative (−)
- Formula result < 0 means a decrease
- Example: 100 → 75 = −25%
How to Calculate Percentage Change
Follow these three simple steps to compute the percentage change between any two values manually.
Find the Difference
Subtract the initial value (V₁) from the final value (V₂) to find the absolute change.
Divide by Original
Divide the difference by the absolute value of the original number, |V₁|. This normalises the change.
Multiply by 100
Convert the ratio to a percentage by multiplying it by 100. Add the % sign to the result.
Worked Example — Salary Increase
Your salary rises from £2,000 to £2,400. What is the percentage increase?
Percentage Change Examples
Click any example card to instantly load the values into the calculator above.
Product Price Drop
Account Balance Recovery
Loss Worsens Further
Monthly Rent Increase
Town Population Growth
Factory Output Decline
Common Use Cases
Percentage change is one of the most widely used calculations across finance, business, science and everyday life.
Investment Returns
Track stock, crypto, or portfolio performance over a period.
Salary Changes
Measure annual raises, bonus impact or job-offer comparisons.
Price & Inflation
Compare product prices, rent rises, or inflation over years.
Business KPIs
Revenue growth, conversion rates, churn and profit margins.
Science & Research
Express experimental differences and measurement changes.
Education
Grade improvements, attendance rates and test score changes.
Common Percentage Mistakes
These are the most frequent errors people make when computing percentage change — and how to avoid them.
Dividing by the new value instead of the original
Always divide by the original (V₁) value, not V₂. Dividing by the new number reverses the meaning of the change.
Forgetting the absolute value for negative originals
When V₁ is negative, use |V₁| in the denominator. Without it, the sign of the result becomes wrong.
Confusing percentage change with percentage of
"What is 20% of 50" (=10) is different from "What is the % change from 50 to 10" (=-80%). Don't mix them up.
Dividing by zero
If V₁ = 0, percentage change is undefined. Use a different metric (e.g., absolute change) in that case.
Mixing increase and decrease in one direction
An increase from 100 to 150 is +50%, but a decrease from 150 to 100 is only −33.33%. They are not symmetric.
Frequently Asked Questions
Quick answers to the most common questions about percentage change calculation.
Percentage change measures how much a value has increased or decreased relative to its original value, expressed as a percentage. It's calculated using the formula (V₂ − V₁) ÷ |V₁| × 100. A positive result indicates growth, while a negative result indicates a decline. Learn more on Wikipedia's percentage article.
Use the three-step method: (1) subtract the original value from the new value to find the difference, (2) divide that difference by the absolute value of the original, and (3) multiply by 100 to convert to a percentage. See the step-by-step guide above.
Percentage change compares a new value to a known original value (directional, uses |V₁| as denominator). Percentage difference compares two values with no clear "original" — it divides by the average of the two values instead. Use percentage change when one value is clearly the starting point; use percentage difference when comparing two equal-status values.
Yes. If the new value is more than double the original, the increase exceeds 100%. For example, going from 100 to 300 is a +200% change. Likewise, going from 100 to 0 is a −100% change (a complete loss). Values beyond ±100% are perfectly valid.
Use the absolute value of V₁ in the denominator. For example, changing from −25 to 25: (25 − (−25)) ÷ |−25| × 100 = 50 ÷ 25 × 100 = 200% increase. Without the absolute value, the result would incorrectly come out negative. This calculator handles that automatically.
Percentage change is undefined when V₁ = 0, because division by zero is impossible. In this case, use the absolute change (V₂ − 0 = V₂) or describe the change in words ("value increased from 0 to 50"). This calculator will display a clear message if you enter 0 as the initial value.
Percentage change is the umbrella term that covers both increase (positive result) and decrease (negative result). Percentage increase refers specifically to cases where the new value is greater than the original. So all increases are changes, but not all changes are increases.
Because the denominator (the original value) changes. Going from 100 to 150 is +50% (50 ÷ 100). Going back from 150 to 100 is −33.33% (−50 ÷ 150). The absolute change is the same (£50), but the percentage differs because the base changed. This is normal and expected behaviour.
Use the formula =(B2-A2)/ABS(A2)*100 where A2 is the original value and B2 is the new value. Format the cell as a number with a % sign, or remove the *100 and apply Excel's built-in percentage format. For more, see Microsoft's official guide.
Percentage points measure the arithmetic difference between two percentages (e.g., interest rate rising from 5% to 7% = 2 percentage points). Percentage change would describe that same rise as a 40% increase ((7−5)/5×100). They describe the same event in different ways — pick the one that matches your context.
Authoritative Resources
External references to deepen your understanding of percentage calculations.