CDN Calculator

CDN Calculator

Content Delivery Network (CDN) charges are always an online video concern. Even when content delivery is a secondary cost driver, it is a variable that can only be predicted and one that increases with a video’s success.

CDNs generally charge a monthly fee and then some form of usage or overage component with the usage/overage being charged on a viewer hour or GB delivered basis. Viewer hours, which is the total time that a video has been watched (number of plays x average time watched each play or number of unique viewers x average time watched for each unique viewer) is the most human-understandable means of measuring a video’s consumption, but CDN providers sell delivery and most charge on the basis of GB (GigaBytes) delivered.

The formula for converting viewer hours to GB delivered is:

GB delivered / Viewer Hours delivered = kbps / 2330

… where kbps (kilobits per second) is the average streaming bit rate of the video and 2330 is a multiplier generated from converting seconds to hours and bits to bytes. (Note, the 2330 multiplier assumes kilo means 1024. Kilo is sometimes interpreted to mean 1000, if so, the multiplier should be 2386 – but the result will only be a little different).

To practically apply the formula: for a video that has been streamed at an average bitrate of 900kbps and has been watched by 10 people, each of whom have watched it for 10 minutes on average, the number of BigaBytes (GBs) delivered by the CDN is calculated by:

GB delivered = Viewer hours x kbps / 2330

= 10 people x 10 minutes/60 minutes  x 900 kbps / 2330

= 0.64 GB

CDN charges vary dramatically depending on the volume of video generated. High volume CDN users typically pay $0.06 per GB or less for delivery by the leading CDNs whilst average volume users pay $0.25/GB or more. Second and third tier CDNs generally charge less.

For the above example and a CDN charge of $0.25/GB, the total delivery cost of the video would be 0.64 GB x $0.25/GB = $0.16