We examine a graphene quantum dot formed by combining an electric and a uniform magnetic field. The electric field creates a smooth quantum well potential while the magnetic field induces an exponential tail to the dot states. The states peak in the well and the electrostatic barrier region as a result of the Klein tunneling effect. Coupling between dot states which peak in different regions can be achieved with the electric and magnetic fields. The tunability of this dot with moderate external fields could be used for designing quantum devices in monolayer graphene.