Percentage Calculator
Solve any percentage problem — find a percent, what percent, or percentage change.
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How to Calculate Percentages
A percentage expresses a number as a fraction of 100. The word comes from the Latin "per centum," meaning "by the hundred." Percentages appear in everyday life constantly — sales discounts, tax rates, interest rates, test scores, tip calculations, and nutritional labels all use percentages.
There are three core percentage calculations that cover virtually every scenario you'll encounter:
Type 1: Finding a percentage of a number
To find P% of N, multiply N by P and divide by 100: Result = (P × N) / 100. For example, 20% of 150 = (20 × 150) / 100 = 30. This is the most common type — used for calculating discounts, tax amounts, tips, and commissions.
Type 2: Finding what percent one number is of another
To find what percent A is of B, divide A by B and multiply by 100: Percent = (A / B) × 100. For example, 30 out of 150 = (30 / 150) × 100 = 20%. This is used for test scores, market share calculations, and comparing parts to a whole.
Type 3: Percentage change
Percentage change measures how much a value increased or decreased relative to its starting point: % Change = ((New − Original) / Original) × 100. A positive result means an increase (percentage growth); a negative result means a decrease. This is used for year-over-year comparisons, price changes, and performance metrics.
Adding and removing percentages
To add P% to a number N: multiply by (1 + P/100). To remove P% from a number: multiply by (1 − P/100). To reverse-calculate the original before a percentage was applied: divide by (1 + P/100) for an increase, or (1 − P/100) for a discount.
Percentage vs. percentage points
These are often confused. If an interest rate rises from 4% to 6%, that is a 2 percentage point increase — but a 50% relative increase. "Percentage change" is always relative to the original value; "percentage points" measure absolute differences between two percentages.
Frequently Asked Questions
Multiply the number by the percentage divided by 100. For example, 20% of 150 = 150 × 0.20 = 30. Alternatively, think of it as moving the decimal two places: 20% = 0.20.
Divide the part by the whole, then multiply by 100. Example: 30 out of 150 = (30 ÷ 150) × 100 = 20%. This is the "what percent" form of the percentage equation.
Subtract the original from the new value, divide by the original, then multiply by 100. Formula: ((New − Original) / Original) × 100. Positive = increase, negative = decrease.
If a value after applying a percentage is known and you need the original, divide by (1 + percent/100). Example: a price of $120 is 20% more than the original. Original = 120 ÷ 1.20 = $100.
Percentage change is relative. If a rate goes from 10% to 15%, that is a 5 percentage point increase — but a 50% relative increase. Percentage points measure absolute differences between two percentages.
Multiply by (1 + percent/100). To add 15% to 200: 200 × 1.15 = 230. To subtract 15% from 200: 200 × 0.85 = 170.