📝 How to Calculate Percentage in Excel (Simple, Human-Friendly Guide)

If you use Excel even a little, you already know how useful percentages can be — marks, discounts, salary hikes, GST, sales growth… everything depends on them.
The good news? Excel can calculate all of this with one simple idea:

👉 Percentage = Part / Total

Once you understand this, every percentage problem becomes easy.

Let’s walk through it step by step — with real examples, not boring theory.

⭐ 1. How to Find a Basic Percentage in Excel

Imagine you scored 45 marks out of 50.
In Excel, enter:

• A1 → 45
• B1 → 50

Now type this formula:

=A1/B1

Press Enter → then click the % button.
You’ll instantly get 90%.

That’s it — this is the core of everything.

⭐ 2. Percentage of Marks (Most Common Use)

Let’s say your marks look like this:

Subject	Scored	Total
Math	78	100
Science	72	100

Use:

=B2/C2

Then apply the percentage format.
Excel will handle the rest.

⭐ 3. How to Calculate Percentage Increase

A salary example always makes this simple.

Old salary: ₹30,000
New salary: ₹35,000

Place them in two cells and use:

=(New – Old) / Old

In Excel:

=(35000-30000)/30000

After formatting → 16.67% increase.

You can use the same idea for sales, traffic, revenue — anything that goes up.

⭐ 4. How to Calculate Percentage Decrease

Suppose a product drops from ₹1200 to ₹900.

Formula:

=(Old – New) / Old

Excel:

=(1200-900)/1200

You’ll get 25% decrease.

⭐ 5. Percentage Change (General Formula)

When you don’t know whether a value increased or decreased:

=(New Value – Old Value) / Old Value

If the result is positive → increase
If negative → decrease

⭐ 6. How to Find Discount Percentage

Original price: ₹1500
Sale price: ₹1200

Use:

=(1500-1200)/1500

Result → 20% discount

Works perfectly for ecommerce price analysis.

⭐ 7. Calculate GST Percentage in Excel

If GST amount = ₹180 and base price = ₹1000:

=180/1000

Result → 18%

⭐ 8. Convert a Decimal Into a Percentage

If a cell has 0.25, just select it → press %.

You instantly get 25%.

💡 Quick Reference Table

Purpose	Formula
Basic percentage	=Part/Total
Percentage increase	=(New–Old)/Old
Percentage decrease	=(Old–New)/Old
Discount %	=(Original–Sale)/Original
Marks %	=Marks/Total
GST %	=GSTAmount/BasePrice

❗ Common Mistakes Beginners Make

• Forgetting to press the % button
• Using New instead of Old in the wrong place
• Adding text inside numeric cells
• Leaving blank cells in formulas
• Typing values manually instead of using A1, B1 references

✔ Final Thoughts

Excel isn’t scary when you break it down.
Every percentage problem — marks, growth, discount, salary hike, GST — works on the same formula.
Once you use cell references and keep values clean, Excel will do the maths for you.

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