CalcMate

Percentage Calculator

Work out percentages instantly: what is X% of Y, X is what percent of Y, and percentage increase or decrease between two numbers.

How to use the percentage calculator

Pick the question you need to answer, enter your two numbers, and the result appears instantly. The three modes cover almost every everyday percentage problem:

What is X% of Y? — the classic discount and tip question. A 15% tip on a $64 bill, a 30% discount on a $89 jacket, or 8% sales tax on a purchase all use this mode.

X is what percent of Y? — turns a fraction into a percentage. Scoring 42 out of 60 on a test, finishing 7 of 20 tasks, or comparing a part to its whole all fit here.

Percentage change — measures growth or decline between two values: price changes, salary raises, follower growth, or year-over-year sales.

The three formulas

All percentage math reduces to three formulas. Percentage of a number: (X ÷ 100) × Y. Part as a percentage of a whole: (X ÷ Y) × 100. Percentage change: ((new − original) ÷ original) × 100. Keeping the base straight — which number you divide by — is the key to getting the right answer.

Frequently Asked Questions

How do I calculate a percentage of a number?

Divide the percentage by 100, then multiply by the number: X% of Y = (X ÷ 100) × Y. For example, 25% of 200 is (25 ÷ 100) × 200 = 50. This is the calculation behind discounts, tips, and tax.

How do I work out what percent one number is of another?

Divide the part by the whole and multiply by 100: (X ÷ Y) × 100. For example, 30 out of 120 is (30 ÷ 120) × 100 = 25%. This is how test scores and completion rates are calculated.

How is percentage change calculated?

Subtract the original value from the new value, divide by the original value, then multiply by 100: ((new − original) ÷ original) × 100. Going from 80 to 100 is a +25% change; going from 100 to 80 is −20%. The two directions differ because the starting base differs.

Why is a 50% increase not cancelled out by a 50% decrease?

Because each step uses a different base. Increasing 100 by 50% gives 150, but decreasing 150 by 50% gives 75, not 100. Percentage changes multiply rather than add, which is a common trap in sales figures and investment returns.

What is the difference between percentage points and percent?

Percentage points measure the absolute gap between two percentages, while percent measures the relative change. If an interest rate rises from 2% to 3%, that is an increase of 1 percentage point but a 50% relative increase.

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