The OpenLDAT project (short for Open Latency Display and Analysis Tool) is a system composed of a self‐buildable device and an open‐licensed application to measure several display latency metrics. The most interesting metric is total system latency: the time between an action happening in the physical world, like a mouse being clicked, and the result being displayed on the screen, such as a muzzle flash from a weapon in a videogame. There is currently no similar device on the market, and this type of measurement is traditionally done manually using a modified mouse and a high speed camera, but OpenLDAT can measure it automatically using a built‐in test, or interactively, allowing testing of virtually any game or application, potentially on a separate machine. In addition to system latency, OpenLDAT can also measure more traditional metrics, such as pixel response times.