This table has many holes and even whole scales missing! Please help by filling in the gaps and writing a bit about them on their designated pages. To find out how go to FAQ.

Gauge- The distance between the inside of the two rails

Scale- The proportion that the model bears to the full size prototype, it can be expressed either as size relationship, 1":1', or a ratio, 1:12 or 1/12.

The full Glossary

Name	Gauge	Scale	mm/foot	Page	Layouts	Notes
Standard	4'8.5"	1:1	304.8	Prototypes		World Standard
Broad	7'	1:1	304.8	Prototypes		Brunel's Gauge
G	45mm	1:24-8	~15	G		Narrow Gauge 3ft
Gn15	16.5mm	1:24	~15	Gn15	Gn15	Representing 15" gauge
SM45	45mm	1:19	16	SM45		Narrow Gauge 3ft
SM32	32mm	1:19	16	SM32		Narrow Gauge 2ft
1	45mm	1:30.5	10	Gauge1	Gauge1
0	32mm	1:43.5	7	0Gauge	OGauge
Scale7	33mm	1:43.5	7
016.5	16.5mm	1:43.5	7			Narrow gauge 2' 3" but used for 2'0" - 2'6"
0n30	16.5 mm	1:48	6..4			USA narrow gauge 2'6"
09	9mm	1:43.5	7			Miniature gauge 15"
S	7/8"	1:64	3/16"	SGauge	S Gauge
H0	16.5mm	1:87.1	3.5	HO	H0	Worlds Most Popular
H0n3	10.5mm	1:87	3.5	HOn3	H0n3
00 00-SF	16.5mm 16.2mm	1:76.2 1:76.2	4 4	OO	00	Uk's Most Popular
00 Broad Gauge	28mm	1:76.2	4			Brunel's Broad Gauge in 00
00n3	12mm	1:76.2	4
009	9mm	1:76.2	4	OO9	009
EM	18.2mm	1:76.2	4	EM	EM
P4	18.83mm	1:76.2	4	P4	P4	Exact Scale 4mm
3mm	14.2mm	1:101.6	3	3mm	3mm
TT	12mm	1:120	2.54	TT	TT
N	9mm	1:148	2	N	N
2mm Finescale	9.42mm	1:152.4	2	2mmfinescale	2mmFinescale
Z	6.5mm	1:220	1.4	Z	Z	Smallest Commercially Available