# Percentile The percentile is the average value of a series using only the smaller N percentile of the values. (a population or a probability distribution). Netdata applies linear interpolation on the last point, if the percentile requested does not give a round number of points. The following percentile aliases are defined: - `percentile25` - `percentile50` - `percentile75` - `percentile80` - `percentile90` - `percentile95` - `percentile97` - `percentile98` - `percentile99` The default `percentile` is an alias for `percentile95`. Any percentile may be requested using the `group_options` query parameter. ## how to use Use it in alarms like this: ``` alarm: my_alarm on: my_chart lookup: percentile95 -1m unaligned of my_dimension warn: $this > 1000 ``` `percentile` does not change the units. For example, if the chart units is `requests/sec`, the result will be again expressed in the same units. It can also be used in APIs and badges as `&group=percentile` in the URL and the additional parameter `group_options` may be used to request any percentile (e.g. `&group=percentile&group_options=96`). ## Examples Examining last 1 minute `successful` web server responses: -  -  -  -  ## References - .