SuperCalc

Percentage Calculator

Five percentage calculations in one place — find a percentage of a number, figure out what percent one value is of another, compute percentage change, or increase and decrease by a percentage. Instant results, no button needed.

Calculator

Percentage Calculator

Choose a calculation mode, enter your numbers, and see the result instantly. No button needed.

%

e.g. 15

e.g. 200

Result

Enter numbers above to see the result

How percentage calculations work

A percentage is a ratio expressed as a fraction of 100. The word itself comes from the Latin "per centum" — per hundred. When you say 15%, you mean 15 out of every 100, or 0.15 as a decimal.

All five modes above are variations of the same core idea: multiply or divide by 100 at the right step. "15% of 200" means 200 × 0.15 = 30. "What percent is 30 of 200?" means 30 ÷ 200 × 100 = 15%.

Percentage change adds a direction: an increase from 200 to 250 is (250 − 200) ÷ 200 × 100 = 25% increase. A decrease from 250 to 200 is (200 − 250) ÷ 250 × 100 = −20%. Note: the base matters — increasing by 25% and then decreasing by 20% gets you back to the original.

FAQ

How do I calculate a percentage of a number?
To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 200 = 200 x 15 / 100 = 30. Use the "% of" mode above and the result appears instantly as you type.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 30 is what % of 200? 30 / 200 x 100 = 15%. Switch to "is what %" mode above to calculate this.
How is percentage change calculated?
Percentage change = ((New Value - Old Value) / |Old Value|) x 100. A positive result means an increase, negative means a decrease. For example, going from 200 to 250 is a 25% increase.
What is the difference between percentage increase and percentage of?
"Percentage of" gives you a portion of a number (15% of 200 = 30). "Increase by percentage" adds that portion to the original (200 increased by 15% = 230). They answer different questions.
Can I use this for tip and discount calculations?
Yes. For tips, use "% of" mode — e.g. 18% of your bill amount. For discounts, use "decrease" mode — e.g. decrease the price by 20%. Both give you instant results.
Are the calculations done on a server?
No. All percentage math runs entirely in your browser — nothing is sent to a server. The results update in real time as you type, with zero network latency.

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