Bolometric corrections (BCs) for Galactic WR stars, calculated from the data given in Fig. 1, as a function of surface temperatures. The thick dashed line gives the best fit to the data. The thin lines denote the BCs calculated by Maund et al. (2005) from the Potsdam WR-star synthetic spectra of Gräfener et al. (2002), for the minimum (dotted line), median (dashed line), and maximum (dot-dashed line) transformed radii R_t (see Maund et al. for details).