Percentage Calculator

How to calculate a percentage

1. Choose Percentage of a number, What percentage?, or Find the whole. Changing the question clears the two entries so their meanings cannot be confused.
2. Enter the two labelled values. For 15%, type 15 without the % sign. Use the same units for an amount and its whole.
3. Read the result and the question below it. About means the displayed value was rounded; an interval preserves a tiny nonzero answer.
4. Open Calculation details for the selected formula, or copy the qualified summary. Use the dedicated Percentage Change or Discount tool for those different questions.

Three useful percentage questions

• Find an amount such as 15% of 200 without converting the percentage by hand.
• Find what percentage one number represents of another, including results above 100%.
• Recover the whole from a known amount and the percentage it represents.
• Use signed decimal values with explicit zero, rounding and tiny-result explanations.
• Calculate in your browser with two active inputs, one answer and no upload or account.

Everyday percentage calculations

• Work out a known share of a quantity, such as 15% of 200 units.
• Express a count or measured amount as a percentage of a comparable total using the same unit.
• Reconstruct a total when an amount and its percentage are both known, without inferring any tax, grading or financial rule.

Understanding amount, percentage and whole

Percent means per hundred. To find an amount, divide the entered percentage by 100 and multiply by the number. For example, 15% of 200 is 30.

To find the percentage, divide the amount by the whole and multiply by 100. An amount of 30 out of a whole of 200 is 15%. Reversing the two numbers asks a different question.

To recover the whole, divide the known amount by the percentage and multiply by 100. If 30 is 15% of the whole, the whole is 200. A percentage entry of 0.15 means 0.15%, not 15%.

Zero is a valid number. Finding 0% of a number gives 0. An amount of 0 compared with a nonzero whole gives 0%, but a percentage with a zero whole is undefined. In the inverse question, 0 at 0% has no unique whole, while a nonzero amount at 0% has no finite solution.

Percentages may exceed 100, and signed inputs follow ordinary algebra without changing a negative denominator to its absolute value. For example, −30 as a percentage of −200 is 15%. These are direct proportions, not a claim that something increased or decreased.

Use ungrouped digits and up to four decimal places. A comma is always decimal, so 1,000 means 1 and one thousand must be entered as 1000. Exact entered decimals are retained; only the result display rounds to at most six places, with About or a strict signed interval where needed.

Percentage calculation examples

Percentage of a number: 15% of 200 = 30. Enter 15 as the percentage and 200 as the number.

What percentage: 30 out of 200 = 15%. An amount of 150 out of 100 is 150%, which is valid arithmetic.

Find the whole: 30 is 15% of 200. Enter 30 as the amount and 15 as the percentage.

Signed values: −15% of 200 = −30; −30 as a percentage of −200 = 15%. These examples use ordinary signs, not a growth convention.

Rounding and zero: 1 as a percentage of 3 is about 33.333333%. A zero whole has no defined percentage, while finding a whole from amount 0 and percentage 0 has no unique answer.

What this calculator does not decide

A direct percentage, a percentage change, a percentage difference and percentage points are different calculations. This tool provides only the three selected proportion questions.

The amount and whole must use the same units and a meaningful comparison basis. A mathematical result does not establish whether data are comparable or a real-world interpretation is appropriate.

Each input is limited to a magnitude of 1,000,000,000, four decimal places and 32 raw characters. Scientific notation, typed percent signs, fractions and digit grouping are not accepted.

The result is a unitless arithmetic calculation, not currency rounding, a tax or interest policy, a grade assessment, investment advice or a compounded percentage model.

Your entries and copied result

This calculator processes entries in your browser without putting the numbers or result in the page address or calculator storage. Copy result intentionally puts the inputs and qualified answer in your clipboard. This is not a claim that the whole site has no analytics or third-party requests.

The calculator does not save drafts. Changing the question clears its inputs; Clear returns to Percentage of a number with blank inputs. Normal language navigation reloads those defaults, so copy any result you need before leaving.