12 mm
# 12 mm

12 mm or 12 mm gauge may refer to:

## Rail transport modelling

* TT gauge, 1:120 scale with rails 12 mm apart, representing standard gauge
* HOn3½ gauge, 1:87.1 scale with rails 12 mm apart, representing 3-foot-6-inch gauge
* H0m, 1:87 scale with rails 12 mm apart, representing metre gauge
* 00n3, 1:76 scale with rails 12 mm apart, representing 3-foot gauge
* 5.5 mm scale, 1:55 scale with rails 12 mm apart, representing narrow gauge
* On2 gauge, 1:48 scale with rails 12.7 mm apart, representing narrow gauge

## Firearms

* 12 mm caliber
