Calculate X% of Y, find what percent one number is of another, and work out percentage increase or decrease with instant results.
This free percentage calculator helps with common percentage math in one place. Use it to solve what is X% of Y, X is what percent of Y, percentage increase and percentage decrease without doing the formula by hand.
Results update as you type, and you can use whole numbers or decimals.
A percentage is a number expressed out of 100. When you see 25%, it means 25 out of every 100. Percentages make it easier to compare values, understand proportions, and explain part-to-whole relationships in a simple way.
They are used everywhere: exam scores, discounts, salary increases, savings rates, sales growth, and data comparisons. Instead of comparing raw numbers alone, percentages make the difference easier to understand at a glance.
The basic percentage formula is used when you want to know what percent one number is of another.
For example, if you score 45 out of 60 on a test, the calculation is:
(45 ÷ 60) × 100 = 75%. That means you scored 75%.
Use this formula when you already know the part and the whole and want the answer as a percentage.
Use this method when you know the percentage and want to find the actual value it represents.
20% of 150 = 30
15% of 300 =
45
12.5% of 800 = 100
This is useful for working out discounts, tax amounts, tips, commissions, and any case where you need a share of a total.
To find what percent one number is of another, divide the first number by the second and multiply by 100.
75 is what percent of 250?
(75 ÷ 250) × 100 =
30%
Use this when you know both values and want to express their relationship as a percentage. It is common for scores, completion rates, conversions, and comparisons.
Percentage increase shows how much a value has grown compared with its original amount.
From 80 to 100
((100 − 80) ÷ 80) × 100 =
25% increase
This is useful for salary raises, traffic growth, revenue increases, pricing changes, and follower growth.
Percentage decrease shows how much a value has gone down compared with its original amount.
From 200 to 150
((200 − 150) ÷ 200) × 100 =
25% decrease
Use this for markdowns, traffic drops, falling sales, reduced expenses, and any situation where a number declines over time.
Percentage change is the general formula used when comparing an original value with a new one. If the result is positive, it is an increase. If the result is negative, it is a decrease.
Example: if a price moves from 40 to 52, the result is 30% increase. If sales drop from 500 to 425, the result is 15% decrease.
Here are the main formulas in one place for quick reference.
These worked examples make it easier to check your answer or understand the formula in context.
| Question | Formula Applied | Result |
|---|---|---|
| What is 20% of 150? | (20 ÷ 100) × 150 |
30 |
| What is 15% of 300? | (15 ÷ 100) × 300 |
45 |
| 45 is what percent of 60? | (45 ÷ 60) × 100 |
75% |
| 75 is what percent of 250? | (75 ÷ 250) × 100 |
30% |
| Percentage increase from 80 to 100? | ((100−80) ÷ 80) × 100 |
25% ↑ |
| Percentage decrease from 200 to 150? | ((200−150) ÷ 200) × 100 |
25% ↓ |
Percentage calculations are simple, but small mistakes can give the wrong answer.
Percentage calculations are useful in everyday life, school, shopping, business, and finance.
Looking for something more specific? Try one of these related tools.