How to calculate a percentile
✓ Verified in LibreOffice 25.8.7.3 ✓ Verified in Google Sheets (2026-08-30)Find the value below which a given share of the data falls — the 90th-percentile response time, the top-quartile cutoff, the median (50th).
The formula
| App | Formula | Notes |
|---|---|---|
| Excel (desktop) | =PERCENTILE.INC(A2:A100,0.9) | 0.9 = 90th percentile; use 0.5 for the median, 0.25/0.75 for quartiles. PERCENTILE() is the older alias for PERCENTILE.INC. |
| Google Sheets | =PERCENTILE(A2:A100,0.9) | PERCENTILE here matches Excel's .INC (inclusive). PERCENTILE.EXC also exists for the exclusive method. |
| LibreOffice Calc | =PERCENTILE(A2:A100,0.9) | Identical; PERCENTILE.INC/.EXC also supported. |
How it works
A percentile marks the value below which a given fraction of the data sits: the 90th percentile is the point 90% of values fall under. PERCENTILE.INC sorts the numbers and interpolates — for {10,20,30,40} at 0.5 (the median) it lands halfway between 20 and 30, giving 25. Feed 0.25 and 0.75 for the lower and upper quartiles, or 0.9 for the classic 90th-percentile latency metric. There are two conventions: PERCENTILE.INC (inclusive, the default and what plain PERCENTILE uses) always includes the 0th and 100th points, while PERCENTILE.EXC (exclusive) excludes them and needs enough data for the requested rank — the two disagree most on small samples, so state which you used. For the inverse — 'what percentile is this value?' — use PERCENTRANK. QUARTILE is just PERCENTILE fixed at 0/25/50/75/100.
Verified, not just documented
We ran =PERCENTILE.INC(A2:A5,0.5) in LibreOffice 25.8.7.3 (headless, with forced recalculation) and it returned 25 — exactly the expected result. We then ran the same formulas in Google Sheets, executed 2026-08-30: a formula-only workbook goes into Google Drive, which converts it to a Sheet and recalculates every formula with Google’s own engine, and comes back out as .xlsx carrying the values Google computed. It returned 25 for the worked example, the same value LibreOffice produced. Both engines’ numbers on this page are executed results. The Excel formula follows Microsoft’s official documented syntax — we do not run desktop Excel.
Functions used
PERCENTILE.INC · PERCENTILE — see full Excel, Google Sheets & LibreOffice compatibility for each.