To calculate your total dedicated tenancy hours, use the below formula.
(on-demand hours) = (total compute hours) - (reserved instance hours)
(total dedicated tenancy hours) = (total hours) - (total compute hours)
The first formula can be written:
(total compute hours) = (on-demand hours) + (reserved instance hours)
Here is a sample dataset for reference:
In this example, (total compute hours) = 744 (on-demand hours) + 0 (reserved instance hours). Now that we have total compute hours and total hours, we can calculate total dedicated tenancy hours. (total dedicated tenancy hours) = 1,488 (total hours) - 744 (total compute hours).
This can be validated by checking the dedicated cost per hour in the statement detail. If we divide the 1,383.84 (EC2 Dedicated Tenancy Cost) by the 744 (total dedicated tenancy hours), we get the expected $1.86 per hour.