The Percentage Calculator helps you quickly find percentages, percentage changes, and percentage differences. Whether you need to calculate a tip, work out a discount, or find what percentage one number is of another, this tool handles it all.
Simply enter your values and get instant results. The calculator supports three common percentage operations: finding a percentage of a number, determining what percentage one number is of another, and calculating percentage change between two values.
Your calculations will appear here
A percentage expresses a number as a fraction of 100. The term derives from the Latin "per centum", meaning "by the hundred". Percentages appear throughout daily life in contexts such as discounts, tax rates, interest, exam scores, and statistical analysis.
The five core percentage operations each serve a distinct purpose. "X% of Y" converts the percentage to a decimal and multiplies. "What % is X of Y" divides the part by the whole and multiplies by 100. "Percentage change" measures how much a value has increased or decreased relative to its original. "Percentage difference" compares two values symmetrically using their average as the base. "Reverse percentage" finds the original whole when you know a part and what percentage it represents.
Percentage change can be positive (increase) or negative (decrease) and uses the absolute value of the original as the denominator. Percentage difference is always non-negative because it uses the absolute difference divided by the absolute average, making it useful when neither value is clearly the "original".
Problem: What is 15% of 240?
Solution: Convert 15% to a decimal: 15 / 100 = 0.15. Multiply: 0.15 * 240 = 36.
Answer: 36
Problem: What percentage is 45 of 180?
Solution: Divide the part by the whole: 45 / 180 = 0.25. Multiply by 100: 0.25 * 100 = 25.
Answer: 25%
Problem: A product price rose from 80 to 100. What is the percentage change?
Solution: Difference: 100 - 80 = 20. Divide by original: 20 / 80 = 0.25. Multiply by 100: 0.25 * 100 = 25.
Answer: 25% increase
Problem: What is the percentage difference between 40 and 60?
Solution: Absolute difference: |40 - 60| = 20. Average: (40 + 60) / 2 = 50. Divide: 20 / 50 = 0.4. Multiply by 100: 0.4 * 100 = 40.
Answer: 40%
Problem: 36 is 15% of what number?
Solution: Convert 15% to a decimal: 15 / 100 = 0.15. Divide: 36 / 0.15 = 240.
Answer: 240
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