The ROI metric does not really apply to VoIP in isolation, since it is a pure service. There is little upfront cost and rarely any capital expense to deploy VoIP, and as such, it really isn't an investment. The benefit of VoIP is primarily based in lower telephony costs, and there is no investment element to speak of. To gauge the value of VoIP, the metrics are tied to the monthly savings in telephone expenses -- long distance, a la carte features, MACs, etc. These are usually expressed in percentage terms compared to what the business was spending previously. It is not unusual to hear of businesses reducing their monthly telecom costs by 20% or more when using VoIP.
These explanations of VoIP and ROI are quite basic, but are worth reiterating, as VoIP is often used interchangeably with IP telephony. They are distinct elements for businesses transitioning from TDM, and sometimes VoIP is considered part of an IP telephony solution. However, the distinction should always be kept in mind – VoIP is a service, and IP telephony usually refers to the hardware and/or software used with a VoIP service.
This was first published in August 2009