HO Scale Calculator

HO is the most popular model railroad scale in the world, running on 16.5 mm gauge track at a ratio of 1:87.1. At HO scale, a 87 cm real measurement becomes about 1 cm on the model.

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What fits at 1:87.1 (1:87)

Model railroads, trackside buildings, vehicles and figures. The huge HO ecosystem makes almost any prototype available.

Real subject	Real size	1:87.1 model
40 ft boxcar	12.2 m	14 cm
EMD F7 locomotive	15.4 m	17.7 cm
Two-storey house (height)	8 m	9.2 cm
Person	1.8 m	2.1 cm

Frequently asked questions

What scale is HO?

HO is 1:87.1, running on 16.5 mm gauge track. It is the most widely produced model railroad scale.

How tall is an HO figure?

A 1.8 m person is about 20.7 mm tall in HO scale (1800 mm ÷ 87.1).

Related scales

→ See all scales