Abstract Flow uniformity among individual channels within a microchannel array can be a significant factor affecting the performance of laminated structured micro-devices. In this study, numerical modeling is used to quantitatively investigate the impact of the geometry of the right triangular manifold and the dimensions of microchannels on desired uniformity and pressure drop. The CFD tool COMSOL is used to perform the simulations within the low-Reynolds number system (5≤Re≤25). In our biomedical application, it is important to have low dead volume and residence time in the manifolds. A methodical approach is introduced to identify a design that balances low manifold volume and maintenance of flow uniformity. It has also been shown that including a short vertical spacing at the corner of manifolds is critical to achieving a high level of flow uniformity. Careful analysis and physical interpretation of trends herein enables a more intuitive approach to array design.