The determination of user perceived delay in audio and video conferencing systems/services is described. Example embodiments consistent with the present invention measure delays in audio and/or video conferencing systems and services, by treating such systems and services as black boxes, thereby providing end-to-end delays as they would be perceived by users. For example, the user perceived round-trip delay in a video conference system/service may include time delays from each of video capture, video encoding, video transmission, video decoding and video rendering.