Top quark width: Theoretical update

A critical assessment of the available calculations of the top quark width is presented. QCD corrections, the finite mass of the $b$ quark, and the effect of the $W$ width are included as well as the electroweak corrections. The relative importance of these corrections is demonstrated for a realistic range of top quark masses. For the QCD corrected decay rate we use the formulas from Eilam et al. and include the electroweak correction taken from Fujii. Our results differ from those available in the literature because all the later calculations ignored the effect of the $W$ width discussed earlier by Eilam et al. This leads to an effect comparable in size to the electroweak correction.