Efficiency of noncircular fins circumscribing circular tubes is generally determined by one of two approximate techniques, the equivalent annulus method or the sector method. In the present work the predictions of these two methods are compared with results obtained from a semianalytical technique for square, hexagonal, and eccentric annular fins. It is observed that the accuracy of the equivalent annulus method reduces with the increase of the two-dimensionality of the fins. However; the sector method guarantees very close agreement with the semianalytical technique over a wide range of parametric variations for all the fins. An improved definition of fin efficiency for the sector method is also put forward to take care of the heat loss from fin tips. Finally it is shown that the optimum dimensions of the fins determined by the sector method closely match the predictions of the semianalytical technique.