Percentage Calculator
Three common percentage calculations in one tool. Enter two numbers and get an instant result — no button press required.
Calculation type
What is X% of Y?
Percentage formulas used
- X% of Y — multiplies Y by X/100. Useful for finding a tip amount, a tax value, or a commission.
- X is what percent of Y? — divides X by Y and multiplies by 100. Useful for grade calculations and proportion analysis.
- Percentage change — calculates
((end − start) / |start|) × 100. A positive result is an increase; negative is a decrease.
Common examples
- Sales tax: What is 8.5% of $49.99? Answer: $4.25
- Test score: 43 is what percent of 50? Answer: 86%
- Price change: percentage change from $80 to $95? Answer: +18.75%
Frequently Asked Questions
How do I calculate what percentage one number is of another?
Divide the part by the whole, then multiply by 100. For instance, 45 out of 60 is (45 / 60) × 100 = 75%.
What is the formula for percentage increase or decrease?
Percentage Change = ((Final Value - Initial Value) / |Initial Value|) × 100. A positive outcome represents an increase, while negative indicates a drop.
What is the difference between percentage and percentage points?
Percentage points measure the absolute arithmetic difference between two rates. For example, moving from 4% to 5% is a 1 percentage point rise, but a 25% relative increase.
How do I find the initial value before a percentage increase?
Divide the final value by (1 + Percentage / 100). For example, if a price is $120 after a 20% markup: Original Price = $120 ÷ (1 + 0.20) = $120 ÷ 1.20 = $100.
Can a percentage increase exceed 100%?
Yes. A 100% increase means a number doubled (from 50 to 100). A 200% increase means it tripled (from 50 to 150), and a 500% increase means it became 6 times the original value.
Can a percentage decrease exceed 100%?
For real physical quantities like price, weight, or distance, a decrease cannot exceed 100% because reaching 0 represents a complete 100% reduction. Greater than 100% decrease would produce negative numbers.
How do I calculate percentages in Excel or Google Sheets?
To find X% of value Y: enter `=Y * X%`. To calculate the percentage change between cell A1 (old) and B1 (new): enter `=(B1 - A1) / A1` and format the cell as Percentage.
Are calculations private?
Yes. All arithmetic operations execute 100% locally within your client browser tab with zero tracking or remote logging.