Dv10, Dv50 and Dv90: Percentiles Are Not a Maximum Size

A median or upper percentile summarizes a distribution. It should not be presented as the largest particle in the material.

Interpret the Notation

Malvern Panalytical explains Dv50 as a volume-median diameter and identifies Dv10 and Dv90 as common volume-weighted percentiles. The v matters: these are volume-based proportions, not automatically proportions of particle count.

Keep the distribution and its basis alongside the reported values. An upper percentile leaves part of the distribution beyond it. A percentile alone therefore cannot establish a maximum particle size for a passage or tooling clearance question. Primary characterization reference.

Illustrative Summary

An invented report gives Dv10 = 10 µm, Dv50 = 40 µm and Dv90 = 90 µm. Using a declared span definition of (Dv90 − Dv10)/Dv50 gives 2.0. These hypothetical values summarize breadth; they do not say that every particle is no larger than 90 µm.

Two distributions can also share a median while differing in their fine or coarse tails. The practical comparison should retain those parts of the report where they matter to the question. Do not use span as an unexplained universal powder-quality grade.

Ask for the Needed Evidence

If the enquiry concerns the presence of occasional large particles, state that requirement and ask the material owner which assessment addresses it. Keep percentile statistics separate from a maximum-size or oversize criterion and its sampling method.

Complete the worksheet with notation, technique, tail information and the intended conclusion. For vial powder filling, this helps prevent a median label from being copied into a tooling limit. The actual product passage and dosing assessment still require the selected equipment and sample evidence. HM equipment context: Vial Powder Filling Machine.