Percentage calculator
Work out percentages, percent change, and a percentile of a list of numbers.
Runs locally in your browser. Nothing is uploaded.
The percentage tab
Three calculations sit on the first tab. “What is X% of Y?” multiplies the percentage by the total and divides by 100. Eight percent of 250 is 20. “X is what percent of Y?” divides the part by the whole and multiplies by 100. The whole cannot be zero, because there is no percentage of nothing. “Percent change” is (new − old) / old × 100. From 80 to 100 is an increase of 25%. From 100 to 80 is a decrease of 20%. Those two are different because the base changed. A drop of 20 percentage points is not the same sentence as a drop of 20 percent, and this calculator always means the ratio, not a subtraction of two percentages.
Negative bases follow the same formula. The sign comes from the arithmetic, so read it with the numbers in front of you. Empty fields stay quiet. A result appears when both numbers are filled in. The unit converter is the better tool when the question is about bytes or milliseconds rather than a ratio.
The percentile tab
A percentile says where a value sits in a sorted list. The 90th percentile is not “90 percent of the first number.” Switch to the Percentile tab, paste the observations separated by commas, spaces, or newlines, and choose the percentile and the method.
Inclusive interpolation matches the common spreadsheet function PERCENTILE.INC. The rank is (p / 100) × (n − 1) on the sorted list, and the result blends the two nearest values. Zero returns the minimum and 100 returns the maximum. Exclusive interpolation matches PERCENTILE.EXC. It uses (p / 100) × (n + 1) and refuses the endpoints and any rank that falls outside the sample. A short list cannot support an extreme exclusive percentile, and the page says so. Nearest rank takes the smallest index whose cumulative share reaches the requested percentile, using ceil(p / 100 × n), and it returns the minimum at zero.
With the five numbers 1, 2, 3, 4, and 5, the inclusive 25th percentile is 2, the inclusive median is 3, and the exclusive 20th percentile is 1.2. Say which method you used when you quote the number. Small samples move a lot when you add one observation. A percentile from a handful of scores is a description of that handful, not a property of a larger population.
Common questions
Which percentile method should I use?
Use inclusive when you want the same answer as a typical spreadsheet, including the minimum and the maximum. Use exclusive when you are matching PERCENTILE.EXC. Use nearest rank when you want an actual observation from the list rather than a blend of two.
Why did percent change and “percentage points” disagree?
Percentage points are a subtraction: 30% minus 25% is 5 percentage points. Percent change divides by the starting value. This page computes percent change. Name the unit when you write the sentence.
Can I paste a column from a spreadsheet?
Yes. Commas, spaces, semicolons, and line breaks are all separators. A token that is not a number is reported so a stray word does not become a zero.
Are the numbers uploaded?
No. Both tabs run in the page. A list of scores or salaries stays in the browser.