Gauge ( ) may refer to:

Measurement

Gauge (instrument) In science and engineering, a dimensional gauge or simply gauge is a device used to make measurements or to display certain Physical dimension, dimensional information. A wide variety of tools exist which serve such functions, ranging from simple ...

, any of a variety of measuring instruments *

Gauge (firearms) The gauge (in American English or more commonly referred to as bore in British English) of a firearm is a unit of measurement used to express the inner diameter (bore diameter) and other necessary parameters to define in general a smoothbore Gun b ...

Wire gauge Wire gauge is a measurement of wire diameter. This determines the amount of electric current the wire can safely carry, as well as its electrical resistance and weight. Types of wire gauge Wire gauges may be broadly divided into two groups, t ...

, a measure of the size of a wire ** American wire gauge, a common measure of nonferrous wire diameter, especially electrical **

Birmingham gauge The Birmingham gauge, officially the Birmingham Wire Gauge and often abbreviated as ''G'' or ''ga'', is unit or wire gauge used to measure the thickness or diameter of wires and tubing, including hypodermic needles and other medical tube products. ...

, a measure of ferrous wire and hypodermic needle diameter **

Jewelry wire gauge Jewelry wire is wire, usually copper, brass, nickel, aluminium, silver, or gold, used in jewelry making. Wire is defined today as a single, usually cylindrical, elongated strand of drawn metal. However, when wire was first invented over 2,000 ye ...

, the size of wire used in jewelry making *

Sheet metal gauge Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Thicknesses can vary significantly; extremely thin sheets are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate, ...

, thickness of metal in sheet form *

Film gauge Film gauge is a physical property of photographic film, photographic or Film stock, motion picture film stock which defines its width. Traditionally, the major movie film gauges are 8 mm film, 8 mm, 16 mm film, 16 mm, 35 mm movie film, 35 mm, an ...

, a physical property of film stock which defines its size * The size of objects used in stretching (body piercing), especially earrings *

Gauge block Gauge blocks (also known as gage blocks, Johansson gauges, slip gauges, or Jo blocks) are a system for producing precision lengths. The individual gauge block is a metal or ceramic block that has been precision grinding (abrasive cutting), grou ...

, a metal or ceramic block of precisely known dimension, used in measuring * Sight glass, also known as a water gauge, for measuring liquid level heights in storage tanks and pressure vessels * Boost gauge, a gauge used in conjunction with turbo-super-chargers * Pressure gauge or vacuum gauge, see

pressure measurement Pressure measurement is the measurement of an applied force by a fluid (liquid or gas) on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of pressu ...

* Gauge pressure, pressure above ambient pressure *

Stream gauge A stream gauge, streamgage or stream gauging station is a location used by hydrologists or environmental scientists to monitor and test terrestrial bodies of water. Hydrometric measurements of water level surface elevation (" stage") and/or v ...

, for measuring height and discharge of a river or stream * Air core gauge, a type of rotary actuator often used in automotive instruments * Gauger, one who gauges or measures, typically dutiable commodities, such as wine, landed from ships at docks

Sizes

Railway practice

Track gauge In rail transport, track gauge is the distance between the two rails of a railway track. All vehicles on a rail network must have Wheelset (rail transport), wheelsets that are compatible with the track gauge. Since many different track gauges ...

, the distance between the two rails forming a railway track *

Loading gauge A loading gauge is a diagram or physical structure that defines the maximum height and width dimensions in railway vehicles and their loads. Their purpose is to ensure that rail vehicles can pass safely through tunnels and under bridges, and k ...

, the maximum width and height of vehicles (engines, loaded wagons, etc.). *

Structure gauge A structure gauge, also called the minimum structure outline, is a diagram or physical structure that sets limits to the extent that bridges, tunnels and other infrastructure can encroach on rail vehicles. It specifies the height and width of s ...

, the minimum size of bridges, tunnels, platforms, etc. * Axle load, the weight that an axle exerts on track * Variable gauge, system to allow railway vehicles to travel across a break of gauge

Medicine

, for metal wire and tube products * French gauge, mainly for catheters

Mathematics and physics

Gauge theory In physics, a gauge theory is a type of field theory in which the Lagrangian, and hence the dynamics of the system itself, does not change under local transformations according to certain smooth families of operations (Lie groups). Formally, t ...

Gauge integral Gauge ( ) may refer to: Measurement * Gauge (instrument), any of a variety of measuring instruments * Gauge (firearms) * Wire gauge, a measure of the size of a wire ** American wire gauge, a common measure of nonferrous wire diameter, especial ...

Gauge fixing In the physics of gauge theories, gauge fixing (also called choosing a gauge) denotes a mathematical procedure for coping with redundant degrees of freedom in field variables. By definition, a gauge theory represents each physically distinct co ...

Gauge boson In particle physics, a gauge boson is a bosonic elementary particle that acts as the force carrier for elementary fermions. Elementary particles whose interactions are described by a gauge theory interact with each other by the exchange of gauge ...

* Gauge (

Minkowski functional In mathematics, in the field of functional analysis, a Minkowski functional (after Hermann Minkowski) or gauge function is a function that recovers a notion of distance on a linear space. If K is a subset of a real or complex vector space X, ...

)

Other uses

Gauge (knitting) The term "gauge" is used in knitting to describe the fineness size of knitting machines. It is used in both hand knitting and machine knitting. The phrase in both instances refers to the number of stitches per inch rather than the size of the fini ...

, the number of stitches in a given length * Gauge (actress), American pornographic actress * Gauge (band), post-hardcore band from Chicago, Illinois, USA * Gauge, Inc., a manufacturer of microphones and audio accessories *

Change of gauge (aviation) In air transport, a change of gauge for a passenger or cargo flight is a change of aircraft that retains the same flight number.Gauge (software) Gauge is a light weight cross-platform test automation tool. It uses markdown to author test cases and scenarios. Its modular architecture makes it flexible and scalable. Markdown Gauge specifications are written in the business language. For ex ...

, cross-platform test automation tool