Percentage Calculator
Enter numbers to easily calculate percentages.
Percentage of a number
Percentage increase or decrease
What percentage is one number of another?
How percentages work
A percentage is simply a part out of 100. Every problem comes down to three basic questions:
What is 20% of 80?
Multiply the percent by the number, then divide by 100.
16 is what % of 80?
Divide the part by the total, then multiply by 100.
16 is 20% of what?
Multiply the part by 100, then divide by the percent.
3 common mistakes to avoid
Easy traps to look out for in school, shopping, and everyday math:
Points vs. percent change
If an interest rate moves from 10% to 15%, that is an increase of 5 percentage points, but a 50% jump in the rate itself.
The 50% drop trap
If an investment loses 50%, you need a 100% gain just to get back to even. A 50% gain only brings you halfway back.
Reversing sales tax
For a $113 total with 13% tax included, divide by 1.13 to find the $100 price. Subtracting 13% gives $98.31, which is incorrect.
Specialized percentage calculators
Select any calculator below for fast, step-by-step solutions with exact decimal precision.
Core Math
10 Calculators
Money & Shopping
7 Calculators
School & Grades
3 Calculators
Sports & Fitness
2 Calculators
Frequently asked questions
Simple explanations for everyday math questions:
How do you calculate percentage of a number?
To find P percent of a number X, multiply P by X and then divide by 100. Formula: Result = (P × X) ÷ 100. For example, to find 15% of 80: (15 × 80) ÷ 100 = 1,200 ÷ 100 = 12.
How do you calculate what percent one number is of another?
To find what percent A is of B, divide A by B and multiply by 100. Formula: Percentage = (A ÷ B) × 100. For example, 19 out of 95 is (19 ÷ 95) × 100 = 0.20 × 100 = 20%. Note that B cannot be zero.
What is the difference between percentage change and percentage points?
Percentage change measures relative growth compared to the initial value: ((New − Old) ÷ |Old|) × 100. Percentage points is the simple difference between two percentage rates: New% − Old%. For example, an increase from 10% to 15% is a 5 percentage point increase (15 − 10 = 5 points), but a 50% relative increase ((15 − 10) ÷ 10 × 100 = 50%).
Why do standard online calculators make rounding errors?
Standard calculators use binary floating-point numbers where decimals like 0.1 cannot be represented precisely. For example, (0.5 × 201 ÷ 100) produces 1.00 in standard JavaScript instead of the mathematically correct 1.01. PercentagesCalculators uses 40-digit arbitrary-precision decimal arithmetic to guarantee 100% exact solutions.