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We show that for metal/graphene/dielectric sandwich structures, charge doping in graphene depends on both the work functions of the metal and the dielectric. Using C-1s core level photoemission spectroscopy we determine the charge doping in graphene for one-sided metal contacts as well as for sandwich structures that are commonly used in graphene devices. The measured Fermi-level shifts are in good agreement with a model that predicts that the difference in charge doping for graphene on a metal compared to graphene sandwiched between a metal and dielectric is given by ΔEF ≈ 0.44 × √(Φmetal − Φdielectric).