Percentile Calculator
Drop in a list of numbers, pick a percentile, and see exactly which value sits at that point in the data.
How it works
First the numbers get sorted from smallest to largest. A percentile is just a position in that sorted line — the 90th percentile is the point below which 90% of your values fall.
For the exact spot we use linear interpolation. Multiply the percentile (as a fraction) by one less than the count to get a rank, then blend the two neighboring values by how far the rank sits between them. That's why the answer often lands between two of your numbers.
Say you've got 12, 15, 18, 22, 27, 31, 40, 55 and you want the 75th percentile. The rank is 0.75 × 7 = 5.25, so we take the value at index 5 (31) plus a quarter of the gap to index 6 (40) — landing at 33.25.
Frequently asked questions
What does the 90th percentile actually mean?
It's the value that 90% of your data sits at or below. If a test score is in the 90th percentile, only about 10% of scores were higher — a handy way to rank a single number against a whole group.
Why isn't the answer one of my original numbers?
Because the exact percentile usually falls between two of your values, and interpolation splits the difference. With small lists that's common. If you want a value straight from the data, round the percentile to line up with a real position.
Is a percentile the same as a percentage?
Not quite. A percentage is a share of a whole; a percentile is a ranking within a distribution. Scoring 80% on a test is your raw grade — being in the 80th percentile means you beat 80% of test-takers.
How many numbers do I need?
One works, though it's not very interesting — the answer is just that number. The tool shines with a real dataset. There's no upper limit, so paste as many as you like, separated by commas, spaces, or new lines.