In this study, we compared microchannel droplet formation in a microfluidics device with a two phase lattice Boltzmann simulation. The droplet formation was found to be qualitatively described, with a slightly smaller droplet in the Simulation. This was due to the finite thickness of the interface in the simulations. Dependence on dispersed flow Fate could be very nicely predicted by the model, while a better insight was obtained on the internal pressures and flow velocities during droplet formation. These were found to be well described by simple relations; (1) the pressure inside the dispersed phase was predicted very well by the Laplace pressure while (2) the flow rate through the neck could be estimated by the flow through an orifice. These insights simplify the development of design rules for new microchannel devices. (C) 2009 Elsevier Inc. All rights reserved.