Percentage Calculator

The percentage calculator helps you solve three essential percentage problems instantly.

What is a Percentage?

A percentage (%) represents a number or ratio expressed as a fraction of 100. It is a dimensionless way to express proportions and compare values at the same scale.

• Symbol: % (percent)
• Meaning: Per hundred, or out of 100
• Decimal equivalent: 25% = 0.25
• Example: 25% of $200 = 0.25 ×$200 = $50

Percentages are everywhere: discounts in stores (30% off), grades in school (85% on a test), interest rates on savings accounts (2.5% per year), and tax rates (8% sales tax).

Three Problem Types

1. Finding X% of Y

This is the most common percentage problem. You have a percentage and a base value, and you want to find what portion that percentage represents.

Formula: (X ÷ 100) × Y

Example: What is 25% of 200?

• (25 ÷ 100) × 200 = 0.25 × 200 = 50

Real-world use: If a shirt costs $200 and is marked 25$50, so you pay $150.

2. Finding What Percentage X is of Y

You have two values and want to know what percentage the first represents of the second. This answers questions like “what grade did I get?” or “what is my market share?”

Formula: (X ÷ Y) × 100

Example: 50 is what % of 200?

• (50 ÷ 200) × 100 = 0.25 × 100 = 25%

Real-world use: If you scored 75 points out of 100 on a test, your percentage is (75 ÷ 100) × 100 = 75%.

3. Percentage Change

Percentage change measures how much a value has increased or decreased relative to its original value. It’s crucial for tracking growth, inflation, and performance metrics.

Formula: ((New − Old) ÷ Old) × 100

Example: A stock price went from $100 to$150. What is the percentage change?

• ((150 − 100) ÷ 100) × 100 = (50 ÷ 100) × 100 = 50%

Interpretation:

• Positive result = increase (growth)
• Negative result = decrease (loss)
• Zero = no change

Real-world use: If your salary increases from $50,000 to$55,000, your raise is ((55000 − 50000) ÷ 50000) × 100 = 10%.

How to Use the Calculator

1. Select your problem type from the dropdown:

   • “X% of Y” to find a portion
   • “X is what % of Y” to find the percentage
   • “Percentage change from X to Y” to find growth or decline

2. Enter your values in the input fields (labels change based on your selection)

3. Click Calculate to instantly see your result

4. Review the explanation to understand how the answer was computed

Worked Examples

Example 1: 35% of 450

You want to find 35% of 450.

• Select “X% of Y”
• Enter 35 in “Value 1” and 450 in “Value 2”
• Result: 157.5

Calculation: (35 ÷ 100) × 450 = 0.35 × 450 = 157.5

Use case: If a product costs $450 and has a 35$157.50.

Example 2: 84 is what % of 120?

You scored 84 points out of 120 on a test. What’s your percentage?

• Select “X is what % of Y”
• Enter 84 in “Value 1” and 120 in “Value 2”
• Result: 70%

Calculation: (84 ÷ 120) × 100 = 0.70 × 100 = 70%

Interpretation: You achieved a 70% score.

Example 3: Percentage Change from 200 to 260

Your revenue grew from $200,000 to$260,000. What’s the percentage growth?

• Select “Percentage change from X to Y”
• Enter 200 in “Value 1” (old) and 260 in “Value 2” (new)
• Result: 30%

Calculation: ((260 − 200) ÷ 200) × 100 = (60 ÷ 200) × 100 = 30%

Interpretation: Your revenue increased by 30%.

Frequently Asked Questions

Can a percentage be more than 100%?

Yes! A percentage greater than 100% means the new value exceeds the original. For example:

• If you invest $1,000 and it grows to$2,500, your return is ((2500 − 1000) ÷ 1000) × 100 = 150%

Can a percentage be negative?

Yes! A negative percentage indicates a decrease:

• If a stock price falls from $100 to$75, the change is ((75 − 100) ÷ 100) × 100 = −25%

Why is percentage change different from just subtracting?

Percentage change considers the context of the original value. A $50 increase means different things:

• Growing from $50 to$100 = 100% increase (doubled)
• Growing from $500 to$550 = 10% increase (modest growth)

Both increased by $50, but the percentage tells you the relative change.

How do I calculate a percentage discount?

Find the discount amount using “X% of Y”, then subtract from the original price:

• Original price: $80
• Discount: 25% of $80 = (0.25) × 80 =$20
• Final price: $80 −$20 = $60

Or use our percentage change tool backward.

What’s the difference between percentage points and percent change?

• Percentage points: Simple arithmetic difference. If a tax rate rises from 8% to 10%, it’s a 2 percentage point increase.
• Percent change: Relative increase. The tax rate increased by (10 − 8) ÷ 8 × 100 = 25% (in relative terms).