How to use formulas when creating dashboards?

[Avinash_Pattnaik]

Hello,

I am new to kibana and need a bit of help in creating a dashboard. I have the metrics i need to create a dashboard. for one of the columns, i need to use some arithmetic to determine the value of a column.

for e.g for column C, i need the value to be the difference between column A and column B. How can i do that using formula?

Here in the attached snip, i need the new column to be the difference between total size and used size.

[Avinash_Pattnaik]

This worked.

subtract(last_value(cluster.disk.capacity.tb),last_value(cluster.disk.usage.tb))