General hard X-ray bolometric correction in the 2–10 keV band as a function of the bolometric correction for type 1 and type 2 AGN. Symbols are the same as in Fig. 4. Black hexagons are the average bolometric correction values, in bins of bolometric luminosity. The black solid line is our best-fit solution; the brown solid line is the analytical prediction obtained by assuming the relation between the X-ray luminosity and the optical luminosity by Lusso & Risaliti (2016) and the optical bolometric correction by L12. See text and Table 1 for details.