%Math Tool

Percentage Calculator

Calculate any percentage quickly. Find X% of a number, what percent one number is of another, percentage change, and add or subtract percentages.

1What is X% of Y?

What is% of?
Example: What is 15% of 200? Answer: 30

2X is what % of Y?

is what % of?
Example: 30 is what % of 200? Answer: 15%

3Percentage Change

Example: From 100 to 150 = +50% increase

4Add or Subtract Percentage

Example: 100 + 10% = 110, 100 − 10% = 90

Common Percentages Reference

5%
= 0.05
= 1/20
10%
= 0.1
= 1/10
12.5%
= 0.125
= 1/8
20%
= 0.2
= 1/5
25%
= 0.25
= 1/4
33.33%
= 0.333
= 1/3
50%
= 0.5
= 1/2
66.67%
= 0.667
= 2/3
75%
= 0.75
= 3/4
100%
= 1
= 1/1

Percentage Formulas

Find X% of Y

Result = (X ÷ 100) × Y

Example: 20% of 150 = (20 ÷ 100) × 150 = 30

X is what % of Y?

Percent = (X ÷ Y) × 100

Example: 30 is what % of 150? = (30 ÷ 150) × 100 = 20%

Percentage Change

Change = ((New − Old) ÷ Old) × 100

Example: 100 to 125 = ((125 − 100) ÷ 100) × 100 = 25%

Add/Subtract Percentage

Result = Value × (1 ± Percent/100)

Example: 100 + 15% = 100 × 1.15 = 115

Percentage Tips & Tricks

🔄 The Flip Trick

X% of Y = Y% of X. So 8% of 50 = 50% of 8 = 4. Use whichever is easier to calculate!

➗ Breaking Down Percentages

To find 15%, find 10% and 5% separately. 15% of 80 = 8 (10%) + 4 (5%) = 12

💡 Quick 10% Rule

To find 10%, just move the decimal point one place left. 10% of 250 = 25

Related Tools

Common Uses for Percentage Calculations

🛒

Shopping Discounts

Calculate sale prices, discounts, and how much you save. Find the final price after 20% off.

💰

Finance & Taxes

Calculate interest rates, tax amounts, tips, and investment returns.

📊

Business Analytics

Track growth rates, profit margins, market share, and performance metrics.

🎓

Academic Grades

Calculate test scores, grade percentages, and weighted averages.

🏋️

Health & Fitness

Track body fat percentage, calorie goals, and workout progress.

📈

Data Analysis

Compare statistics, calculate ratios, and analyze trends in data.

Frequently Asked Questions

How do I calculate a percentage of a number?▼

Divide the percentage by 100, then multiply by the number. For example, 25% of 80: (25 ÷ 100) × 80 = 0.25 × 80 = 20. Our calculator does this automatically.

How do I find what percentage one number is of another?▼

Divide the part by the whole, then multiply by 100. For example, what percent is 15 of 60? (15 ÷ 60) × 100 = 25%. So 15 is 25% of 60.

How do I calculate percentage increase or decrease?▼

Subtract the old value from the new value, divide by the old value, then multiply by 100. Formula: ((New - Old) ÷ Old) × 100. A positive result means increase, negative means decrease.

Why is 50% off then 50% off not the same as 100% off?▼

Because each discount applies to the current price, not the original. 50% off $100 = $50. Then 50% off $50 = $25. You paid $25, which is 75% off the original, not 100%.

How do I add tax to a price?▼

Multiply the price by (1 + tax rate/100). For 8% tax on $50: $50 × 1.08 = $54. Or find the tax amount ($50 × 0.08 = $4) and add it to the original price.

What's the difference between percentage points and percent?▼

Percentage points measure the absolute difference between percentages. If interest goes from 5% to 7%, that's a 2 percentage point increase, but a 40% increase (2 is 40% of 5).