O Scale to HO Scale Conversion
To convert a model dimension from O Scale (1:48) to HO Scale (1:87), multiply it by 0.5517 (48 ÷ 87). The result is a smaller model — every length, width, and height changes by the same factor.
Conversion Chart
| O Scale size (mm) | HO Scale size (mm) |
|---|---|
| 1 mm | 0.55 mm |
| 2 mm | 1.10 mm |
| 5 mm | 2.76 mm |
| 10 mm | 5.52 mm |
| 20 mm | 11.03 mm |
| 50 mm | 27.59 mm |
| 100 mm | 55.17 mm |
Frequently Asked Questions
How do I convert O Scale to HO Scale?
Multiply any O Scale model dimension by 0.5517 to get the HO Scale dimension. This works because O Scale is 1:48 and HO Scale is 1:87, so the factor is 48 ÷ 87 = 0.5517.
Is HO Scale bigger or smaller than O Scale?
HO Scale models are smaller: the same subject is only 0.5517× the size in each dimension compared to O Scale.
Keep Exploring
Reverse: HO Scale to O Scale · O Scale (1:48) guide · HO Scale (1:87) guide · Full calculator