Percentage Calculator — Instant & Free
Three calculators in one: find X% of a number, see what percent X is of Y, and measure percentage increase or decrease — with results as you type.
What is X% of a number?
30
Example: 20% of 150 = 30. Useful for tips, discounts, and tax.
X is what percent of Y?
20%
Example: 30 is 20% of 150. Useful for scores, progress, and shares of a total.
Percentage increase / decrease
-25%
decrease
Example: 60 → 45 is a 25% decrease. Useful for price changes, raises, and statistics.
Want the formulas with worked real-life examples (sales, raises, tips)? How to calculate percentage increase & decrease
Frequently Asked Questions
How do I calculate a percentage of a number?▼
Multiply the number by the percentage divided by 100. For example, 20% of 150 is 150 × 0.20 = 30. The first calculator above does this instantly.
How do I work out the percentage increase or decrease?▼
Subtract the old value from the new value, divide by the old value, then multiply by 100. Going from 60 to 45: (45 − 60) ÷ 60 × 100 = −25%, a 25% decrease.
Why is a 50% increase not undone by a 50% decrease?▼
Because the base changes. 100 increased by 50% is 150, but 150 decreased by 50% is 75 — not 100. Percentage changes always apply to the current value, not the original.
What is the difference between percent and percentage points?▼
If an interest rate rises from 4% to 6%, that is a 2 percentage-point rise, but a 50% relative increase. News headlines often mix these up — the calculator gives you the relative change.
Does this calculator work offline?▼
Yes. All three calculators run entirely in your browser with no server calls, so they keep working without an internet connection once the page is loaded.