Scale (H0, N, TT, Z, G)
A scale (in German: Nenngröße) is a standardised model railway size class — it fixes the scale ratio and the track gauge together. The most common scales are:
| Scale | Ratio | Model gauge | Notes |
|---|---|---|---|
| G / IIm | 1:22.5 | 45 mm | garden railway |
| 1 | 1:32 | 45 mm | |
| 0 | 1:45 | 32 mm | |
| OO | 1:76 | 16.5 mm | British standard |
| H0 | 1:87 | 16.5 mm | the most popular scale |
| TT | 1:120 | 12 mm | traditionally strong in Eastern Germany |
| N | 1:160 | 9 mm | second most popular, space-saving |
| Z | 1:220 | 6.5 mm | smallest series-produced scale |