How to read model scale ratios
A scale ratio says how many real-world units each unit on the model stands for. It's a pure ratio, so it works the same in millimetres, inches or anything else.
1:N, 1/N and "N scale"
1:35, 1/35 and "35th scale" all mean the same thing: one unit on the model stands for 35 units of the real thing. A 3.5 m car becomes 100 mm long, and a 35 ft boat becomes 1 ft. The bigger the second number, the smaller the model. A 1:144 airliner is about a quarter the length of the same airliner at 1:35.
Ratios below 1:1, such as 2:1, are enlargements, used for things like oversized insect or watch-movement models. The converter accepts both, as well as decimal ratios such as 1:76.2.
Inch-per-foot scales
Dollhouse, architecture and some railway traditions name a scale by how much model length stands for one real foot. Since a foot is 12 inches, convert by dividing 12 by the model inches:
| Name | Model length per real foot | Ratio |
|---|---|---|
| One-inch scale (standard dollhouse) | 1 in | 12 ÷ 1 = 1:12 |
| Half-inch scale | ½ in | 12 ÷ 0.5 = 1:24 |
| Quarter-inch scale | ¼ in | 12 ÷ 0.25 = 1:48 |
| 7 mm scale (British O gauge) | 7 mm | 304.8 ÷ 7 = 1:43.54 |
| 4 mm scale (British OO) | 4 mm | 304.8 ÷ 4 = 1:76.2 |
The last two mix metric model sizes with imperial real feet, which is why OO works out to the unusual 1:76.2.
Worked example: a door at three scales
A typical interior door around 2,040 mm tall and 820 mm wide (an illustrative size, since doors vary by country) becomes:
- 1:12: 170 × 68.3 mm
- 1:35: 58.3 × 23.4 mm
- 1:72: 28.3 × 11.4 mm
Each figure is just the real size divided by N. Check them in the reference library by picking each scale.
Scale is not figure size, and not track gauge
Wargaming sizes ("28 mm") give the height of a figure, not a ratio. See heroic scale. Railway names like "HO" or "N" set both a scale and a track gauge. See railway scales and gauges.
Area and volume don't scale linearly
If every length shrinks by 35, a surface shrinks by 35² = 1,225 and a solid by 35³ = 42,875. This matters for material estimates, weight and paint, and it's why a 1:6 figure needs far more resin than twice a 1:12 one. Doubling linear size multiplies volume by eight.