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Percentage calculator

Choose whether to find an amount, a share of a total, or a percentage change. Enter the two numbers to calculate and copy the result.

Inputs must be non-negative numbers. Results use a decimal point and comma thousands separators, regardless of your browser language.

What is this percentage of the number?

Enter the numbers, then select Calculate.

Choose the calculation

Use Percentage of a number for 15% of 200, Find a percentage for 42 out of 50, or Percentage change to compare an original value with a new one.

Enter a percentage as a number

For 15%, enter 15 without the % sign. Inputs accept up to 6 decimal places; do not add units or use a comma as a decimal separator.

Copy or reset

Changing an input clears the old result. Reset clears the active calculation. Copy result places the result on your system clipboard; Reset does not clear that clipboard.

Choose the Right Percentage Calculation

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An amount, a share or a change?

The same two numbers can answer different questions. Finding 15% of 200 gives an amount: 30. Finding what percentage 30 is of 200 gives a share: 15%. Comparing 200 with 230 gives an increase: 15%. Choose the question before entering numbers.

Use matching units when comparing a part with a total or an original value with a new one. For example, compare grams with grams rather than grams with kilograms. This calculator does not convert units.

Work out a percentage of a number

Suppose a group has 200 places and you want to reserve 15% of them. Choose Percentage of a number, enter 200 and 15, and calculate. The result is 30 places because 200 × 15 ÷ 100 = 30. This is an illustrative calculation, not a booking feature.

The percentage field is a percentage number: 15 means 15%, while 0.15 means 0.15%. Values above 100 are allowed. For example, 150% of 200 is 300; the tool does not assume every percentage is part of a fixed whole.

Find a share of the total

If 42 of 50 entries are complete, choose Find a percentage. Enter 42 as the part and 50 as the total. The result is 84%, calculated as 42 ÷ 50 × 100. A part greater than the total produces a result above 100%, which may be valid for a comparison but should prompt a check of your inputs.

The total must be greater than zero. The tool cannot calculate a percentage with zero as the denominator, even when the part is also zero. Enter the actual total rather than substituting a small number to avoid the error.

Compare the new value with the original

For a rise from 80 to 100, enter 80 as the original value and 100 as the new value. The result is a 25% increase: the difference of 20 is divided by the original 80. Swapping the values gives a 20% decrease, not 25%, because the comparison starts from 100.

The original value must be above zero. A change from 0 to a positive number does not have a defined percentage increase using this calculation. This tool accepts non-negative inputs only, so it does not handle comparisons involving negative balances.

Percentage changes are different from percentage-point changes. A rate moving from 20% to 25% rises by 5 percentage points and by 25% relative to its original rate. Entering 20 and 25 in Percentage change gives the relative increase.

Read the precision and keep the result

Each input can be from 0 to 1,000,000,000,000 with up to 6 decimal places. Use a decimal point; correctly grouped thousands commas such as 1,000 are accepted. Negative numbers, units, percent signs and scientific notation are not accepted.

Results are rounded to at most 6 decimal places and marked approximate when a remainder was rounded. A very small non-zero result can therefore display as approximately 0. Keep the original inputs if you need to reproduce or check a rounded result.

The calculation runs in this page and the tool does not send or save your entered numbers. Copying sends the displayed text to your system clipboard, whose history and syncing depend on your device. Clearing the page result does not erase the clipboard.

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