If a function runs, it is my understanding that it is kept in a warm state for a period of 10-15 minutes or so to reduce cold starts.

Is this extra time where it is kept warm charged for?

>Solution :

In the default configuration you are only charged for the execution time of your Cloud Functions (and the memory used during that time).

If you configure a minimum number of instances, you will also be charged (at a lower rate, called idle time) for instances that are kept warm for you.