Examples of Monthly Bandwidth Use

What is the 95th percentile, and why is it useful in measuring bandwidth?

The 95th percentile is the smallest number that is greater than 95% of the numbers in a given set. The reason this statistic is so useful in measuring data throughput is that it gives a very accurate picture of the use and cost of the bandwidth. The advantage to you as the customer is that you get the performance of a high-speed connection, while paying only for actual usage.

It is not possible to accurately calculate the 95th percentile without having all of the samples for a one month period. In order to calculate the 95th percentile for a 30-day period, it is necessary to save an entire 30 days worth of the 5-minute samples. Your billing is based upon these 8,640 samples.

In this example, you would take out the higher 5% of the Max In/Max Out bandwidth measurement from the monthly MRTG graph which is 884 Kbps. You would then take the bottom 94% of the remaining samples taken, in this example that is 337 Kbps. Using this method each 1,000 Kbps is 1 Mbs per month. The percentage of bandwidth per Mbs would be X/1000 or 337/1000 = .337 Mbs or 107 Gb per month. That would be the bandwidth billing for the month.