📈 Percentage Increase and Decrease Explained (With Easy Examples & Tricks)

Percentages are one of those topics that seem simple at first… until you actually start solving questions.

You’ll see them everywhere:

• 🛒 Discounts in shopping
• 💼 Salary hikes and cuts
• 📊 Profit and loss
• 🎓 Exam results

Yet many people still feel confused when asked:

👉 “What is the percentage increase?”
👉 “Why doesn’t a 20% increase cancel a 20% decrease?”

The problem isn’t difficulty—it’s clarity.

In this guide, we’ll break everything down in a way that actually makes sense, using real-life examples, shortcuts, and practical thinking.

💡 What is Percentage? (Quick Understanding)

Percentage simply means:

👉 “Out of 100”

So:

• 50% = half
• 25% = one-fourth
• 10% = one-tenth

👉 This simple idea is the foundation of everything that follows.

📈 What is Percentage Increase?

Percentage increase tells you:

👉 How much a value has grown compared to its original value

🧮 Formula for Percentage Increase

[
\text{Percentage Increase} = \frac{\text{Increase}}{\text{Original Value}} \times 100
]

🧠 Example (Step-by-Step)

Let’s say:

• Original price = ₹1,000
• New price = ₹1,300

Increase = ₹300

👉 Percentage increase = (300 ÷ 1000) × 100 = 30%

⚡ Shortcut Method

Instead of using the formula every time:

👉 Use this:

New Value = Original × (1 + Rate)

Example:

₹1,000 increased by 30%

👉 1000 × 1.3 = ₹1,300

✔️ Faster
✔️ Less calculation

📉 What is Percentage Decrease?

Percentage decrease tells you:

👉 How much a value has reduced compared to its original value

🧮 Formula for Percentage Decrease

[
\text{Percentage Decrease} = \frac{\text{Decrease}}{\text{Original Value}} \times 100
]

🧠 Example

• Original price = ₹1,000
• New price = ₹700

Decrease = ₹300

👉 Percentage decrease = (300 ÷ 1000) × 100 = 30%

⚡ Shortcut Method

👉 New Value = Original × (1 – Rate)

Example:

₹1,000 decreased by 30%

👉 1000 × 0.7 = ₹700

⚖️ Percentage Increase vs Decrease (Clear Difference)

Feature	Increase 📈	Decrease 📉
Meaning	Value goes up	Value goes down
Operation	Add	Subtract
Shortcut	× (1 + rate)	× (1 – rate)

Also Read : Percentage Tricks for Exams 2026 (Fast Calculation Tips)

🔥 Important Concept: Increase and Decrease Are Not Equal

This is where most people make mistakes.

🧮 Example

Step 1:

₹1,000 increased by 20%

👉 ₹1,000 × 1.2 = ₹1,200

Step 2:

Now decrease ₹1,200 by 20%

👉 ₹1,200 × 0.8 = ₹960

🎯 Final Result:

👉 ₹960 ≠ ₹1,000

💡 Why This Happens?

Because:

• Increase is calculated on ₹1,000
• Decrease is calculated on ₹1,200

👉 Different base = different result

🧡 Real-Life Example (Relatable Story)

Let’s say Rahul is buying a laptop.

• Original price = ₹50,000

During festive season:

• Price increases by 10% → ₹55,000

Later:

• A discount of 10% is applied

👉 ₹55,000 × 0.9 = ₹49,500

Rahul expected the price to return to ₹50,000—but it didn’t.

👉 He actually paid ₹500 less.

Lesson:
Percentage changes always depend on the current value, not the original one.

📊 Quick Comparison Table

Original Price	Change	New Price
₹1,000	+10%	₹1,100
₹1,000	-10%	₹900
₹1,000 → ₹1,200 → -20%	₹960
₹50,000 → +10% → -10%	₹49,500

🔁 Successive Percentage Change (Shortcut Trick)

When two percentage changes happen one after another:

👉 Use this formula:

Net Change = a + b + (ab ÷ 100)

🧮 Example 1: Increase + Increase

Increase by 20% and then 10%

👉 20 + 10 + (20×10)/100
👉 20 + 10 + 2 = 32% increase

🧮 Example 2: Increase + Decrease

Increase 20%, then decrease 10%

👉 20 – 10 – (20×10)/100
👉 20 – 10 – 2 = 8% increase

🧠 Everyday Uses of Percentage Change

You use this concept more than you realize:

• 🛒 Discounts while shopping
• 💼 Salary increment
• 📉 Price drops in sales
• 📊 Stock market changes
• 🎓 Exam results

⚠️ Common Mistakes to Avoid

❌ Assuming increase and decrease cancel each other

They don’t—because the base changes.

❌ Using wrong original value

Always compare with the starting value.

❌ Ignoring shortcut methods

They save time, especially in exams.

❌ Not checking final result

Always verify if the answer makes sense.

🧭 Smart Tips for Exams

• ✔️ Use multiplication shortcuts
• ✔️ Avoid long division
• ✔️ Memorize common percentages
• ✔️ Practice daily

📱 Mental Math Shortcut Summary

Situation	Shortcut
Increase	× (1 + rate)
Decrease	× (1 – rate)
Two changes	a + b + (ab/100)

🧡 Another Real-Life Situation

Imagine you’re shopping during a sale:

• Jacket price = ₹2,000
• 25% discount

👉 25% = 1/4

👉 Discount = ₹500
👉 Final price = ₹1,500

Now:

• Additional 10% discount

👉 ₹1,500 × 0.9 = ₹1,350

👉 Total saving = ₹650

Understanding percentages helps you make smarter buying decisions.

Frequently Asked Questions (FAQs) ❓

🎯 Final Thoughts

Percentage increase and decrease is not about memorizing formulas—it’s about understanding how values change.

The key idea is:

👉 Everything depends on the base value

Once you understand that:

• Calculations become easier
• Mistakes reduce
• Confidence improves

One Simple Line to Remember

“Percentages don’t cancel—they compound.”