Percentages show a quantity as a share of 100. Daily questions often use percentages in different directions: finding part of a number, working out a discount, measuring an increase, or comparing an old value with a new one. Keeping those cases separate prevents most mistakes.
1. Find a percentage of a number
To find a percentage of a value, divide the percentage by 100 and multiply by the value.
Example: 15% of 2,500 is 375. Check the same calculation with the Percentage Calculator.
2. Work out a discount
A discount has two useful answers: the amount saved and the final price. First calculate the discount amount, then subtract it from the original price.
final price = original price − savings
If an item costs 5,000 and the discount is 20%, the savings are 1,000 and the final price is 4,000. The Discount Calculator shows both values.
3. Measure percentage change
Percentage change compares how far a new value moved relative to the starting value.
From 80 to 100, the increase is 25%. A starting value of zero does not produce a standard finite percentage-change value, so use a non-zero starting value in the Percentage Change Calculator.
4. Percentage points are different
If a rate moves from 20% to 25%, it increased by 5 percentage points. Relative to the original 20%, however, the percentage increase is 25%. Both statements can be correct, but they answer different questions.
Quick checking habit
Before accepting a percentage result, ask whether the answer should be a part of the original number, a final price, or a relative change between two numbers. That usually tells you which formula belongs to the problem.