A UV tester is an instrument specifically designed to detect and measure the intensity and exposure of ultraviolet radiation (UV). UV rays are usually divided into UVA, UVB, and UVC, and the effects of different bands of UV on organisms and materials vary. Therefore, corresponding UV testers can be used to monitor and evaluate these effects.

UV testers typically include one or more sensors that can sense specific wavelengths of ultraviolet radiation and convert this information into readable data such as UV intensity, exposure time, and cumulative dose. According to usage requirements, there are various types of UV testers, including portable, desktop, and online monitoring systems.