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+<!--
+title: "Percentile"
+description: "Use percentile in API queries and health entities to find the 'percentile' value from a sample, eliminating any unwanted spikes in the returned metrics."
+custom_edit_url: https://github.com/netdata/netdata/edit/master/web/api/queries/percentile/README.md
+-->
+
+# 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:
+
+-   ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=min&after=-60&label=min)
+-   ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=average&after=-60&label=average)
+-   ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=percentile95&after=-60&label=percentile95&value_color=orange)
+-   ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=max&after=-60&label=max)
+
+## References
+
+-   <https://en.wikipedia.org/wiki/Percentile>.