Planning and operation of the bulk power system market require the estimation of the transfer capability margins for a given state of the network. Transfer capability margin defines the maximum amount of the power that can be dispatched for further commercial activity without compromising security or feasibility constraints. Repetitive calculations of such margins is a computationally challenging task mainly due to nonlinearity associated with power flows and feasibility constraints. In this manuscript, we propose a direct algorithm for fast computation of the transfer capability margins with ease of programming. The algorithm is validated on several IEEE test networks with different scenarios.