[[metric-chart]]
=== Metric

A metric visualization displays a single number for each aggregation you select:

include::y-axis-aggs.asciidoc[]
You can click the *Advanced* link to display more customization options:

*JSON Input*:: A text field where you can add specific JSON-formatted properties to merge with the aggregation 
definition, as in the following example:

[source,shell]
{ "script" : "doc['grade'].value * 1.2" }

NOTE: In Elasticsearch releases 1.4.3 and later, this functionality requires you to enable 
{ref}/modules-scripting.html[dynamic Groovy scripting].

The availability of these options varies depending on the aggregation you choose.

Click the *Options* tab to change the font used to display the metrics.