We present results from a detailed simulation of InAs quantum dots embedded in an AlGaAs/GaAs heterostructure with a self-consistent three-dimensional solver of the Poisson-Schrödinger equation based on density functional theory and local density approximation. Single-electron effects in the structure are evaluated by computing the electrochemical potential by means of Slater's transition rule. We have evaluated the effect of strain in the InAs dot on the single-electron charging properties of the system, to assess the importance of including strain in the design of single-electron memories based on self-organized quantum dots.