Calculate percentages instantly. Six different percentage calculations in one place.
A percentage is a number expressed as a fraction of 100. The word comes from the Latin per centum meaning by the hundred. Percentages are used everywhere in daily life — discounts in shops, interest rates on loans, test scores, tax rates, tips in restaurants, and statistical data in news articles all use percentages to express proportions in a way that is easy to compare.
This is the most common percentage calculation. To find X percent of Y, multiply Y by X and divide by 100. For example 15 percent of 200 is 200 times 15 divided by 100 which equals 30. This calculation is used when working out discount amounts, tip amounts, tax amounts, and commission values.
This calculation finds what percentage one number is of another. Divide X by Y and multiply by 100. For example 30 is what percent of 200: 30 divided by 200 times 100 equals 15 percent. This is used when calculating test scores, market share, completion rates, and conversion rates.
Percentage change shows how much a value has increased or decreased relative to its starting value. The formula is the new value minus the old value, divided by the old value, multiplied by 100. A positive result is a percentage increase. A negative result is a percentage decrease. For example if a price goes from 80 to 100, the percentage change is (100 minus 80) divided by 80 times 100 which equals 25 percent increase.
Percentage change is used constantly in finance and economics. Stock prices, revenue growth, inflation rates, and unemployment figures are all expressed as percentage changes to make comparisons meaningful regardless of the absolute values involved.
To increase a number by a percentage, multiply it by 1 plus the percentage divided by 100. To increase 200 by 15 percent: 200 times 1.15 equals 230. To decrease a number by a percentage, multiply by 1 minus the percentage divided by 100. To decrease 200 by 15 percent: 200 times 0.85 equals 170. These calculations are used for applying discounts, adding tax, calculating raises, and working out markups.
This distinction is important and often misunderstood. If an interest rate rises from 2 percent to 3 percent, it has risen by 1 percentage point but by 50 percent. Percentage points describe the absolute difference between two percentages. Percent describes the relative change. Getting this wrong can significantly misrepresent data. Financial news, political reporting, and medical studies frequently mix these up which can be misleading.
Use the first calculator — what is X percent of Y. Enter the discount percentage as X and the original price as Y. The result is the discount amount in pounds or dollars. Subtract that from the original price to get the sale price. For example a 20 percent discount on a 150 pound item: 20 percent of 150 equals 30 pounds discount, so the sale price is 120 pounds.
Use the increase calculator. Enter the price as the number and the tax rate as the percentage. The result is the price including tax. For a price of 100 pounds with 20 percent VAT: 100 increased by 20 percent equals 120 pounds.
Use the last calculator — X is Y percent of what number. Enter the sale price as X and the percentage you paid (100 minus the discount) as Y. For example if you paid 80 pounds after a 20 percent discount, you paid 80 percent of the original price. So 80 is 80 percent of what number: 80 divided by 80 times 100 equals 100 pounds original price.
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