How to Calculate BHCA

Techwalla may earn compensation through affiliate links in this story. Learn more about our affiliate and product review process here.
Heavy traffic strains networks.

When companies design communications networks, they consider how much traffic they expect. The BHCA - busy hour call attempts - represents the average number of times per hour each subscriber tries to make a call. Higher BHCAs strain network processors. Calculate BHCA using subscribers' usage data.


Step 1

Multiply a subscriber's monthly minutes of usage by the percentage of traffic that occurs during working days. For instance, if a subscriber talks for 500 minutes in a month, and 80 percent of calls occur during the work week:

Video of the Day

500 X 0.80 = 400


Step 2

Multiply your answer by the percentage of voice traffic that occurs during the busy hour. For instance, if 10 percent happens during the busy hour:

400 X 0.10 = 40

Step 3

Divide your answer by the number of working days per month. If each month contains 20 working days:


40 / 20 = 2

Step 4

Divide your answer by 60.

2 / 60 = 0.0333.


This answer shows your phone traffic in Erlangs, a unit that represents hours of usage per subscriber per busy hour.


Step 5

Multiply the answer by 3600.

0.0333 X 3600 = 120

Step 6

Divide the answer by mean holding time, in seconds. If your mean holding time is 80 seconds:


120 / 80 = 1.5

This answer is your BHCA.

Video of the Day




Report an Issue

screenshot of the current page

Screenshot loading...