The gauge size is typically referring to the diameter of the dial (ANSI) or case (DIN) for bourdon tube or capsule pressure gauges. The dial is the viewing area of the gauge that shows the pressure scale and needle pointer. Gauges are available in a wide range of sizes from 1" up to 10". Generally, the more accurate gauges are larger and more costly.

The sizes are:

23mm(7/8") diameter dial size

25mm(1") diameter dial size

36mm(1.42") diameter dial size

40mm(1.5") diameter dial size

50mm(2") diameter dial size

63mm(2.5") diameter dial size

70mm(2.75") diameter dial size

76mm(3") diameter dial size

88mm(3.5") diameter dial size

100mm(4") diameter dial size

113mm(4.5") diameter dial size

150mm(6") diameter dial size

200mm(8") diameter dial size

250mm(10") diameter dial size