Percentage Calculator
Tips, discounts, tax, grades: percentages are everywhere. This calculator answers the three questions people ask most, no mental math required.
Switch between modes: a percentage of a value, what percent one number is of another, or the percentage change between two values.
The numbers
Your result
- 20% of 80
- 16
20% of 80 is 16
Before you rely on this
Results are generic estimates using standard time-value-of-money formulas, the same math everywhere. Real-world figures depend on your country's tax rules, rounding, fees, and lender or product terms, which vary by jurisdiction. Treat this as a guide and confirm important numbers with a local professional.
How the percentage calculation works
"X% of Y" multiplies Y by X/100. "A is what percent of B" divides A by B and multiplies by 100. "Percent change" takes the difference between two values and divides by the original.
Percentage change can be negative. A drop from 200 to 150 is a 25% decrease. That's why the original value always goes in the "from" field.
Tips
- Adding tax or a tip? Find the percentage of the bill and add it back to the total.
- An increase followed by an equal percentage decrease does not bring you back to the start.
- For discounts, the percent off is the share of the original price you subtract.
Frequently asked questions
How do I find a percentage of a number?
Multiply the number by the percentage divided by 100. For example, 20% of 80 is 80 × 0.20, which is 16. The calculator's first mode does this instantly.
How do I calculate percentage increase?
Subtract the original value from the new value, divide by the original, multiply by 100. The percent-change mode handles increases and decreases automatically.
What's the difference between percent and percentage points?
Going from 10% to 12% is a 2 percentage-point increase, but a 20% relative increase. This calculator reports the relative change.