Estimations of network demand are an essential input to the IP network planning process. We present a technique for per traffic class IP network demand estimation based on harnessing information gathered for accounting and charging purposes. This technique represents an efficient use of pre-existing information, is easy to deploy, and, crucially, is highly cost- effective in comparison to traditional direct measurement systems employing dedicated traffic metering hardware. In order to facilitate QoS-aware network planning we also introduce a technique for estimation of QoS related effective bandwidth coefficients via analysis of a relatively small number of packet traces. The combination of the demand and effective bandwidth coefficient estimation techniques provide the basis for an effective, low-cost network planning solution. In this paper we present initial results that validate our contention that network accounting records can be reused to create a QoS aware demand matrix for IP networks.