Machine usage daily log and monthly summary

Hi - I am running a business where we rent machines to customers. Each record corresponds to a certain machine. We then have a “status” field with either rented or not-rented. For each machine, this field is then updated manually whenever the status of the machine changes (from “rented” to “not-rented” for example). What I want, is to know at the end of the month, how many days each machine was rented during that month.

Would truly appreciate some help. Thanks.