Background: Unlike medical lasers, intense pulsed light (IPL) devices are largely unregulated and unclassified as to degree of safety hazard. With the exception of most of the USA, the United Kingdom and parts of Europe, the Far East and Australia, the sale of IPLs is generally unrestricted, with the majority being sold into the beauty therapy and spa markets. Standards are only imposed on manufacturers for technical performance data and operating tolerances determined by CE‐compliance under electrical safety standards or the EU Medical Device Directive. Currently, there is no requirement for measurement of key IPL performance characteristics. Objective: To identify the key IPL parameters, emphasize their importance in terms of safe and effective treatment and provide examples of preliminary measurement methods. These measurements can highlight changes in an IPL device's performance, improving patient safety and treatment efficacy. Methods: Five key parameters were identified as having an important role to play in the way light interacts with the skin, and therefore an important role in patient safety and effective treatment. Simple methods were devised to measure the parameters, which include fluence, pulse duration, pulse profile, spectral output and time‐resolved spectral output. Results: The measurement methods permitted consistent and comparable measurements to be made by two of the authors at working clinic locations on 18 popular IPL devices and allowed assessment of output variations. Results showed discrepancies between the measured IPL device outputs and those values displayed on the system or claimed by the manufacturers. The importance of these discrepancies and their impact is discussed. Conclusions: This study, of 18 popular devices in regular daily use in England and Wales, provides example methods for measuring key IPL device parameters and highlights the need for regular measurement of at least those five key parameters measured in this study. These methods can help service technicians to check performance and eliminate device malfunction.