25mm

25 millimeters (25 mm) is a unit of length in the metric system. It equals 0.025 meters and is approximately 0.984 inches. The millimeter is a standard unit for specifying dimensions, tolerances, drilling sizes, and diameters in science, engineering, and manufacturing.

In engineering and construction, 25 mm appears in measurements for fasteners, holes, and piping. For example, pipes and fittings may be described by a nominal diameter of 25 mm. In machining, tools and components are commonly specified by diameter in millimeters, including 25 mm examples.

In photography and cinematography, 25 mm is a common focal length for camera lenses. On full-frame cameras, a 25 mm lens is considered wide-angle, while on smaller or cropped sensors the effective field of view changes with the crop factor.

In miniature wargaming and modelling, 25 mm is used as a scale descriptor for figures and models. The designation refers to the approximate height of typical figures and is historically associated with roughly 1:72 to 1:60 scales. Modern ranges sometimes use other sizes, such as 28 mm or 32 mm, which can vary by manufacturer.

In weaponry, 25 mm describes bore diameter for certain light autocannons. The 25 mm class includes guns such as the Oerlikon 25 mm and the M242 Bushmaster, which fires 25×137 mm ammunition. These weapons are employed on ships, aircraft, and ground vehicles for close-range air defense and light combat roles.