O Scale (1:48) Calculator & Conversion Chart

Traditional Lionel size · 2.08% of real size

American O scale is 1:48 — the traditional Lionel size that dominated toy trains before HO. Note the international split: British O runs 1:43.5 and European O 1:45, so imported stock and figures may read slightly large next to US models.

Precision Scale Conversion Calculator

Real World Size

Scale (1 : N)

Scaled Size

O Scale (1:48) Quick Facts

1 real foot = 0.25″ (6.35 mm) on the model
1 real meter = 20.83 mm on the model
A 6 ft (183 cm) person = 38.1 mm (1.5″) tall
Model is 2.08% of real size — use this as the scale percentage in 3D-print slicers

O Scale (1:48) Reference Chart

Real Size	mm	cm	inches
1 inch	0.529 mm	0.053 cm	0.021″
1 foot	6.4 mm	0.635 cm	0.25″
6 ft (person)	38.1 mm	3.81 cm	1.5″
1 meter	20.8 mm	2.08 cm	0.82″
3 m (room height)	62.5 mm	6.25 cm	2.461″
10 meters	208.3 mm	20.83 cm	8.202″
30 m (building)	625 mm	62.5 cm	24.606″

Frequently Asked Questions

What is O scale in mm, cm, and inches?

In O Scale (1:48), 1 unit on the model equals 48 of the same unit in real life. One real foot equals 0.25 inches (6.35 mm) on the model, one real meter equals 20.83 mm (2.08 cm), and the model is 2.08% of real size.

How tall is a 6 ft person in O Scale (1:48)?

A 6-foot (183 cm) person stands 38.1 mm (1.5 inches) tall in O Scale (1:48).

How do I convert a real measurement to O Scale (1:48)?

Divide the real measurement by 48. For example, a 10 m object is 208.3 mm long in O Scale (1:48). The calculator on this page does this automatically in both directions.