TT Scale Calculator

TT — short for “table-top” — is a 1:120 model railroad scale that fits between N and HO, and it has surged in popularity with new mainstream releases. At TT scale, a 120 cm real measurement becomes 1 cm on the model.

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What fits at 1:120

Space-efficient model railroads that still show good detail; a growing middle ground between N and HO.

Real subjectReal size1:120 model
40 ft boxcar 12.2 m 10.2 cm
EMD F7 locomotive 15.4 m 12.8 cm
Two-storey house (height) 8 m 6.7 cm
Person 1.8 m 1.5 cm

Size comparison at 1:120

Relative model sizes at 1:120 (longest bar = largest model):

1:120 in mm, cm and inches

How common real-world sizes convert to 1:120 model size:

Real sizeModel (mm)Model (cm)Model (inches)
1 m 8.33 mm 0.833 cm 0.328 in
2 m 16.7 mm 1.67 cm 0.656 in
5 m 41.7 mm 4.17 cm 1.64 in
10 m 83.3 mm 8.33 cm 3.28 in
1 ft 2.54 mm 0.254 cm 0.1 in
6 ft (person) 15.2 mm 1.52 cm 0.6 in

Frequently asked questions

What is TT scale?

TT is a 1:120 model railroad scale running on 12 mm gauge track, sized between N (1:160) and HO (1:87).

Is TT bigger than N?

Yes. TT (1:120) is larger than N (1:160) but smaller than HO (1:87).

Related scales

→ See all scales