Percentage Calculator
Calculate percentages three ways: find what percent one number is of another, calculate a percentage of a number, or find the percentage increase/decrease between two values. All instant, all local.
What is X% of Y
X equals what % of Y
Change: From X To Y
About Percentage Calculations
Calculate percentages in multiple ways: find what percent one number is of another, calculate a percentage of a number, or find the percentage increase/decrease between two values.
🔒 All processing happens locally in your browser.
All processing happens locally in your browser — nothing is stored or sent to any server.
How to Use the Percentage Calculator
- Calculate X% of Y: Enter a percentage and a number — get the portion (e.g., 15% of 200 = 30).
- Find what percent X is of Y: Enter a part and a whole — get the percentage (e.g., 30 is 20% of 150).
- Calculate percentage change: Enter an original and new value — get the % increase or decrease.
- Results update instantly as you enter values.
About Percentages
Percentages are one of the most commonly used mathematical concepts in everyday life — from calculating tips and discounts to understanding interest rates and data changes. The word "percent" comes from the Latin "per centum," meaning "by the hundred."
This calculator handles the three most common percentage calculations: finding a percentage of a number (useful for discounts, taxes, and tips), finding what percentage one number is of another (useful for grades, market share, and proportions), and calculating percentage change between two values (useful for comparing price changes, growth rates, and data trends).
All calculations are performed entirely in your browser. No data is stored or transmitted.
Frequently Asked Questions
How do I calculate what X% of Y is? ▼
Enter the percentage (e.g., 15) and the total value (e.g., 200) in the first calculator. Click Calculate and the result will show that percentage of the total (15% of 200 = 30).
How do I find what percent one number is of another? ▼
Use the second calculator. Enter the part (the smaller number, e.g., 30) and the whole (the total, e.g., 150). Click Calculate to see that the part is 20% of the whole.
How do I calculate percentage increase or decrease? ▼
Use the third calculator. Enter the original value and the new value. The result shows the percentage change from the original to the new value. A positive result is an increase, a negative result is a decrease.
What is the formula for percentage change? ▼
Percentage change = ((new value - original value) / original value) x 100. For example, from 50 to 65: ((65 - 50) / 50) x 100 = 30% increase.
Is this tool free to use? ▼
Yes, this percentage calculator is completely free. All calculations happen in your browser — no data is sent to any server.
How do I calculate a discount? ▼
Use the first calculator: enter the discount rate as the percentage and the original price as the total. For a 20% discount on a $80 item, the calculator returns 16, meaning the discount is $16 and you pay $64. To find the final price directly, calculate (100% − discount%) of the original price instead.
How do I calculate a tip from a restaurant bill? ▼
Enter the tip rate (e.g., 18) as the percentage and the bill total as the value. The result is the tip amount. For more advanced cases — splitting between people, rounding the total, or pre-tax vs post-tax tips — use our dedicated tip calculator.
What is the difference between percentage change and percentage points? ▼
A percentage change describes a relative shift: going from 4% to 5% is a 25% increase ((5−4)/4 × 100). A percentage point describes the absolute difference: 5% − 4% = 1 percentage point. News and finance reporting often confuse the two; this matters when interest rates, polls, or unemployment numbers are discussed.