An alternative approach is to consider not an average hour, but to calculate the number of advisors required across a 24-hour day.
This is typically calculated as:
Agents(80%, 30, 20,000 / 7 / 24, 330) x 7 x 24
That is, the number of advisors required per hour in the week multiplied by the number of hours in a week.
The example above gives 2,520 call-taking hours, somewhat higher than the 2,240 calculated above and considerably higher than the accountant’s 1,833 hours.
The reason for this is that spreading the volume across the full 24-hour clock means that the volume per hour is reduced. This increases the amount of availability required to deliver the required service level and hence the number of people you believe you’d need to employ.
If your call centre has an intra-day distribution that really is flat for 24 hours per day, 7 days per week then this is the calculation for you. Most centres will want a different calculation.