Three percentage calculations in one place: N% of a value, what percentage A is of B, and the percentage change between two numbers. A percentage is a ratio out of 100 — 25% means 25 out of 100, or 0.25 — so N% of a value is that value multiplied by N/100.
What is a percentage (%)?
A percentage expresses a ratio out of 100. For example, 25% means 25 out of 100 — that is, 0.25. You find N% of a value by multiplying it by N/100, and percentages show up everywhere in daily life: discounts, interest, taxes, statistics, and more. This calculator brings together the three most common percentage calculations in one place.
How to calculate percentages
- Choose a calculation mode — pick 'Y% of X', 'A is what % of B', or 'Change %' from the tabs at the top.
- Enter the values — type the two numbers the mode needs.
- Calculate — press the button and the result appears instantly.
How do I calculate 'Y% of X'?
Multiply X by Y, then divide by 100. For example, 15% of 200 is 200 × 15 ÷ 100 = 30. Use this method whenever you need 'a certain percent of a base value' — product discounts, value-added tax (VAT), restaurant tips, or fees.
How do I find 'what percent A is of B'?
Divide A by B, then multiply by 100. For example, 30 is 30 ÷ 200 × 100 = 15% of 200. It's handy for exam score percentages, goal completion rates, and each part's share of a whole. If the total (B) is 0 the ratio is undefined, so nothing is calculated.
How do I calculate percentage increase/decrease (rate of change)?
Use (new value − old value) ÷ old value × 100. If the value grows it shows as an increase (positive); if it shrinks, a decrease (negative). For example, going from 200 to 250 is (250 − 200) ÷ 200 × 100 = a 25% increase. It's used for revenue growth rates, price rises and cuts, population change, and more.
What's the difference between a percentage and a percentage point (%p)?
A percentage point (%p) is the arithmetic difference between two percentage values. For example, if an interest rate rises from 3% to 5%, that's a '2%p rise' and at the same time 'about a 66.7% rise'. The difference is that %p is the gap between two ratios, while % is the relative change against a base. This calculator's change-rate mode computes the latter (relative rate of change).