Percentage Change Calculator

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Percentage Change Calculator

Calculate percentage increases or decreases between two values. Simple, fast, and free!

How to Calculate Percentage Change

Our calculator uses this simple formula:

Percentage Change = [(Final – Initial) / Initial] × 100

This works for both increases and decreases.

Practical Uses

Calculate percentage changes for:

  • Price changes and discounts
  • Investment growth
  • Sales performance
  • Weight loss/gain
  • Test score improvements

Why Trust This Calculator

Our tool is built by finance professionals. We use:

  • Standard mathematical formulas
  • Precise calculations
  • Clear explanations

We help thousands calculate percentages monthly.

Percentage Change Calculator: A Complete Guide with Examples

Percentage Change Calculator: How to Calculate % Increase or Decrease

Introduction

Percentage change helps track growth, losses, and trends in business, finance, and daily life. Whether you're checking price hikes, salary raises, or exam scores, knowing how to calculate percentage change is essential.

In this guide, you’ll learn:
✔ The percentage change formula (with easy steps)
✔ Real-life examples (profit, discounts, population growth)
✔ Common mistakes (and how to avoid them)
✔ Free percentage change calculator (Excel/Google Sheets method)

Let’s start with the basics.

What is Percentage Change?

Percentage change measures how much a value has increased or decreased compared to its original amount. It is expressed as a % (percent).

When Do We Use It?

  • Business: Profit/loss calculations
  • Finance: Stock market changes
  • Shopping: Discount percentages
  • Education: Grade improvements
  • Science: Experimental data changes

Percentage Change Formula

The standard formula is:

Percentage Change (%)=Old ValueNew Value - Old Value​×100

How It Works (Step-by-Step)

  1. Subtract the old value from the new value.
  2. Divide the result by the old value.
  3. Multiply by 100 to convert into a percentage.

Example 1: Price Increase

  • Old Price: $50
  • New Price: $75

Calculation:


75−5050×100=50%5075−50​×100=50%


✅ Result: A 50% increase.

Example 2: Population Decrease

  • Old Population: 10,000
  • New Population: 8,500

Calculation:

Calculation:8,500−10,00010,000×100=−15%10,0008,500−10,000​×100=−15%


✅ Result: A 15% decrease.

Types of Percentage Change

1. Percentage Increase

When the new value is higher than the old value.

  • Example: Salary raised from $2,000 to $2,400 → 20% increase.

2. Percentage Decrease

When the new value is lower than the old value.

  • Example: Phone price dropped from $800 to $680 → 15% decrease.

3. No Change (0%)

If the old and new values are the same.

  • Example: Last year’s sales: $5,000 → This year’s sales: $5,000 → 0% change.

Common Mistakes & How to Avoid Them

Mistake 1: Dividing by the New Value (Wrong Denominator)

❌ Wrong: New - OldNew×100NewNew - Old​×100
✅ Correct: Always divide by the Old Value.

Mistake 2: Ignoring Negative Signs

A negative result means decrease. Don’t remove the minus sign!

Mistake 3: Not Multiplying by 100

Forgetting this step gives a decimal (e.g., 0.5 instead of 50%).

Percentage Change Calculator (Excel/Google Sheets Method)

If manual math isn’t your thing, use this formula in Excel/Google Sheets:

= ((New_Value - Old_Value) / Old_Value) * 100

Example:

A (Old Value)B (New Value)C (Formula)D (Result)
200250=(B2-A2)/A2*10025%

(Try it yourself!)

Real-World Applications

1. Business & Finance

  • Stock Market: If a stock moves from $100 → $120, that’s a 20% gain.
  • Inflation Rate: If milk was $2 → $2.20, prices rose by 10%.

2. Shopping Discounts

  • Original Price: $200
  • Discounted Price: $150
  • Savings: 25% off

3. Exam Scores

  • Old Score: 70/100
  • New Score: 85/100
  • Improvement: 21.4% increase

FAQ (Frequently Asked Questions)

Q1. What if the old value is zero?

You can’t calculate percentage change if the old value is zero (division by zero error).

Q2. How is percentage change different from percentage difference?

  • % Change: Compares new vs. old value.
  • % Difference: Compares two unrelated values.

Q3. Can percentage change be over 100%?

Yes! If a value grows more than double, it can be 200%, 500%, etc.

Conclusion

Calculating percentage change is simple if you follow the right formula. Whether you're tracking sales, investments, or grades, this skill is useful everywhere.

Key Takeaways:

✔ Use: New - OldOld×100OldNew - Old​×100
✔ Positive % = Increase | Negative % = Decrease
✔ Avoid common mistakes (wrong denominator, ignoring signs).

Need quick calculations? Try our free percentage change calculator or the Excel method above!

Additional Resources

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