O Scale Calculator

O scale is the classic large model railroad scale, commonly 1:48 in the United States. Its size gives a substantial, detailed feel — at 1:48, a 48 cm real measurement becomes 1 cm on the model.

Scale Converter

Pick a preset or type a ratio — results update instantly.

From
at scale
Scale ratio 1 :
To
at scale
Scale ratio 1 :
Enter a value to convert.

What fits at 1:48 (1:48 (US))

Larger model railroads, toy trains, trackside structures and detailed rolling stock.

Real subjectReal size1:48 model
40 ft boxcar 12.2 m 25.4 cm
EMD F7 locomotive 15.4 m 32.1 cm
Two-storey house (height) 8 m 16.7 cm
Person 1.8 m 3.8 cm

Size comparison at 1:48

Relative model sizes at 1:48 (longest bar = largest model):

1:48 in mm, cm and inches

How common real-world sizes convert to 1:48 model size:

Real sizeModel (mm)Model (cm)Model (inches)
1 m 20.8 mm 2.08 cm 0.82 in
2 m 41.7 mm 4.17 cm 1.64 in
5 m 104 mm 10.4 cm 4.1 in
10 m 208 mm 20.8 cm 8.2 in
1 ft 6.35 mm 0.635 cm 0.25 in
6 ft (person) 38.1 mm 3.81 cm 1.5 in

Frequently asked questions

What ratio is O scale?

In the US, O scale is 1:48. Some European O-scale systems use 1:43.5 or 1:45.

Related scales

→ See all scales