We report on the fabrication and characterization of a low-cost micro-Coulter counter fabricated from biocompatible materials (poly-dimethylsiloxane, glass and gold) and incorporating hydrodynamic focusing. The developed micro-Coulter counter offers a low-cost alternative to equivalent existing devices and, thanks to the hydrodynamic focusing, provides high versatility, being able to probe particles with a wide range of sizes within a single device. The device has been successfully tested for counting 20 latex micro beads in suspension