Work out model scale instantly with clear inputs, formula shown and shareable results.
A scale of 1 : n means every model measurement is n times smaller than reality, so model = real / n and real = model × n. The same units must be used on both sides.
Scale conversion
model = real / n, real = model × n
12000 / 87 ≈ 137.93 mm on the model.
OO is 1:76.2, HO is 1:87, N is 1:148 to 1:160 and O is 1:43.5 to 1:48 depending on the region.