NUMBER TOOL · CLIENT-SIDE
Percentage Calculator
Three ways to calculate percentages: find what percent, calculate a percentage of a value, and measure percent change between two numbers.
Formulas Used
Why use a percentage calculator?
Percentages are everywhere: tax rates, discounts, exam scores, growth metrics, and statistical analysis. This calculator handles the three most common percentage problems so you do not need to remember formulas or do mental math.
Everyday percentage calculations
Shopping discounts
Calculate how much you save with 20% off, or what a 15% tip adds to your bill.
Business metrics
Track growth rates, conversion rates, and month-over-month percentage changes.
Academic scores
Figure out what percentage you got on a test, or how much you need to improve.
Frequently Asked Questions
What are the three percentage calculation modes?
Mode 1: "X is what % of Y" — finds the percentage. Mode 2: "What is X% of Y" — calculates a percentage of a value. Mode 3: "% change from X to Y" — computes percent increase or decrease between two values.
How do I calculate percentage change?
Enter the original value and the new value. The formula is ((new − old) / |old|) × 100. A positive result means increase (shown in green), negative means decrease (shown in red).
Can I use decimals in the calculator?
Yes. The calculator accepts decimal values in all fields. You can enter values like 12.5, 3.33, or 0.75 for precise calculations.