Percentage Change Calculator

Q: What if the old value is negative?

When the old value is negative, the formula still works: use the absolute value of the old value as the denominator. For example, if a company's loss changes from −₹1,00,000 to −₹60,000: ((−60,000 − (−1,00,000)) / 1,00,000) × 100 = 40% improvement.

Find the percentage change between two numbers - whether it's a rise, fall, or no change.

📈 What is Percentage Change?

Percentage change measures how much a value has increased or decreased relative to its original value, expressed as a percentage. It is one of the most widely used calculations in everyday life - from comparing last month's electricity bill to this month's, to tracking stock portfolio returns, salary hikes, weight loss progress, or population growth over a decade.

The key word is relative. A ₹500 increase on a ₹1,000 item (50% change) is dramatically different from a ₹500 increase on a ₹1,00,000 item (0.5% change). Percentage change scales the raw difference against the starting point, making comparisons across different magnitudes meaningful and fair.

A common misconception is confusing percentage change with percentage difference. Percentage change always has a direction - it tells you whether something went up or down from a known starting point. Percentage difference, on the other hand, has no reference direction and is used when comparing two values with equal standing (like two competing prices). Another common mistake is applying a percentage change in reverse: a 50% decrease followed by a 50% increase does not return you to the original value - it leaves you 25% below the start. This happens because each percentage is calculated against a different base.

This calculator accepts any two numeric values - positive, negative, or decimal - and instantly shows you the percentage change, the direction (increase or decrease), and the raw absolute difference. It is useful for students working on maths problems, professionals analysing business metrics, shoppers comparing prices, and anyone who needs to quantify change quickly and accurately.

📐 Formula

Percentage Change = ((New − Old) ÷ |Old|) × 100

New = the new or final value

Old = the original or starting value (the reference point)

|Old| = the absolute value of Old (handles negative starting values)

Positive result = increase | Negative result = decrease

Example: Old = 200, New = 250 → ((250 − 200) / 200) × 100 = +25%

Absolute Difference = |New − Old|

This is the raw numerical change, without the percentage scaling.

Example: |250 − 200| = 50

📖 How to Use This Calculator

Steps to Calculate Percentage Change

Enter the original value - the starting point, old price, initial reading, or baseline number.

Enter the new value - the updated figure you want to compare against the original.

Click Calculate to see the percentage change (with sign), whether it is an increase or decrease, and the absolute difference.

💡 Example Calculations

Example 1 — Salary Hike

Salary increases from ₹45,000 to ₹54,000 per month

Difference: 54,000 − 45,000 = 9,000

Percentage Change: (9,000 / 45,000) × 100 = 20%

Salary increased by 20% | Absolute increase: ₹9,000

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Example 2 — Stock Price Drop

Stock falls from ₹1,200 to ₹900

Difference: 900 − 1,200 = −300

Percentage Change: (−300 / 1,200) × 100 = −25%

Stock decreased by 25% | Absolute drop: ₹300

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Example 3 — Electricity Bill Comparison

Bill goes from ₹2,800 last month to ₹3,360 this month

Difference: 3,360 − 2,800 = 560

Percentage Change: (560 / 2,800) × 100 = 20%

Bill increased by 20% | Absolute increase: ₹560

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Example 4 — Weight Loss Progress

Weight reduces from 92 kg to 78.2 kg over 6 months

Difference: 78.2 − 92 = −13.8

Percentage Change: (−13.8 / 92) × 100 = −15%

Weight decreased by 15% | Absolute loss: 13.8 kg

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❓ Frequently Asked Questions

What is the formula for percentage change?+

Percentage Change = ((New Value − Old Value) / |Old Value|) × 100. A positive result means an increase; negative means a decrease. For example, if a price rises from ₹200 to ₹250: ((250 − 200) / 200) × 100 = 25% increase.

What is the difference between percentage change and percentage difference?+

Percentage change measures movement from an original value to a new value and has a direction (increase/decrease). Percentage difference compares two values with no reference point - it divides the absolute difference by the average of the two values. Use percentage change when one value clearly precedes the other in time.

How do I calculate a percentage decrease?+

Use the same formula: ((New − Old) / |Old|) × 100. When the new value is smaller, the result is negative, indicating a decrease. Example: price drops from ₹400 to ₹300: ((300 − 400) / 400) × 100 = −25%. The decrease is 25%.

Can percentage change exceed 100%?+

Yes. A 100% increase means the value doubled. A 200% increase means it tripled. There is no upper limit to percentage increase. Decreases, however, cannot exceed 100% - a value cannot fall below zero to a meaningful degree.

Why do I get a different result when I reverse old and new values?+

Because percentage change is relative to the starting value. Going from 100 to 200 is a 100% increase. Going from 200 to 100 is a 50% decrease. The numerator is the same (100), but the denominator changes, so the percentage differs.

How do I calculate percentage change in Excel?+

Use the formula =(B2-A2)/ABS(A2)*100, where A2 is the old value and B2 is the new value. ABS() handles the case where the old value is negative. Format the cell as a number or percentage as needed.

What does a 0% change mean?+

It means the old and new values are identical - there has been no change. This happens when New Value equals Old Value exactly.

How is percentage change used in finance and investing?+

In finance, percentage change tracks returns on investments, stock price movements, revenue growth, and profit/loss. For example, if a stock moves from ₹150 to ₹165, the percentage gain is ((165 − 150) / 150) × 100 = 10%. Mutual fund returns, GDP growth rates, and inflation are all expressed as percentage changes.

What if the old value is negative?+

When the old value is negative, the formula uses the absolute value of the old value as the denominator. For example, if a company's loss changes from −₹1,00,000 to −₹60,000: ((−60,000 − (−1,00,000)) / 1,00,000) × 100 = 40% improvement.

How do I find the original value if I know the percentage change and new value?+

Rearrange the formula: Old Value = New Value / (1 + Percentage Change / 100). Example: a price after a 25% increase is ₹500. Original price = 500 / 1.25 = ₹400.

🔗 Related Calculators

📌 Quick Tips

💡A positive result means an increase; a negative result means a decrease. The sign tells you the direction automatically.

💡To find a 20% increase on ₹500, you do not need this calculator - just multiply: 500 × 1.20 = ₹600. Use this calculator when you already have both values.

💡Percentage change is always relative to the original (old) value. Changing from 50 to 100 is a 100% increase, not a 50% increase.

💡When the old value is zero, percentage change is mathematically undefined. You cannot divide by zero.

💡Use percentage change to compare across different scales - a ₹10 change on ₹20 (50%) is far more significant than ₹10 on ₹10,000 (0.1%).