OO Scale Calculator

OO (1:76.2) is the most popular model railway scale in Britain. It runs on the same 16.5 mm track as HO but with slightly larger bodies. At OO scale, a 76 cm real measurement becomes about 1 cm on the model.

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What fits at 1:76.2 (1:76)

British outline model railways, trackside buildings and figures. The huge UK ecosystem makes almost any British prototype available.

Real subjectReal size1:76.2 model
Mk1 passenger coach 19.6 m 25.7 cm
Class 47 locomotive 19.4 m 25.5 cm
Two-storey house (height) 8 m 10.5 cm
Person 1.8 m 2.4 cm

Size comparison at 1:76.2

Relative model sizes at 1:76.2 (longest bar = largest model):

1:76.2 in mm, cm and inches

How common real-world sizes convert to 1:76.2 model size:

Real sizeModel (mm)Model (cm)Model (inches)
1 m 13.1 mm 1.31 cm 0.517 in
2 m 26.2 mm 2.62 cm 1.03 in
5 m 65.6 mm 6.56 cm 2.58 in
10 m 131 mm 13.1 cm 5.17 in
1 ft 4 mm 0.4 cm 0.157 in
6 ft (person) 24 mm 2.4 cm 0.945 in

Frequently asked questions

What is the difference between OO and HO?

Both run on 16.5 mm track, but OO is 1:76.2 and HO is 1:87.1 — so OO models are a little larger for the same track gauge.

How tall is an OO figure?

A 1.8 m person is about 23.6 mm tall in OO scale (1800 mm ÷ 76.2).

Related scales

→ See all scales