Doc_count calculations

Is there any way to use the doc_count value of an aggregation for further calculations?
Below is a part of a terms aggregation result I am working on.
"buckets": [
"key": "All",
"doc_count": 15
"key": "completed",
"doc_count": 10
I need to find the difference between doc_count. for eg:
"key": "InProgress",
"doc_count": 5
Is it possible to get in one query?

It sounds like you want something like Pipeline Aggregations, which allow you to perform computation on metric aggregations.

In particular, you may want to check out the derivative pipeline agg: