Understanding model scale

“Which is closer to HO scale, 1/72 or 1/90?” 

We field this question (or ones like it) pretty often, but just about as frequently, we are asked to help readers understand what scale means. So, let’s get to it! 

When we build and finish a model, whether it’s a single-piece bust, seven-part figure, or a tank with 800 individual pieces, we are making a miniature replica of the full-size version (whether real or imagined). Scale is how we describe the size of the model as a fraction or ratio compared to the full-size subject. If you build a full-size replica, as a group in Russia recently did of the Razor Crest spaceship from The Mandalorian, it is a 1/1 (1:1) scale model. That means 1 inch (or any measurement) on the replica equals 1 inch on the actual subject. If you build a 1/10 scale model, 1 inch on the model would equal 10 inches on the full-size subject. For example, let’s say you model a 1/10 scale replica of a car measuring 10 feet long at full size, the model will be 1 foot long.

Obviously, the larger the denominator in the scale fraction, the smaller the model will be in relation to the real thing, and, therefore, the smaller the scale. A 1/48 scale model is 48 times smaller than its 1/1 scale fellow. A 1/35 scale howitzer is 35 times smaller than the full-size original it is based on.

With the basics out of the way, you start to get into the wonderful world of model scales. Without belaboring the point and sifting through arcane reasons why, you’ll find that certain models are typically made in common scales: 1/35 scale for armor and military-related ground vehicles; 1/72, 1/48, and 1/32 scales for aircraft; 1/20, 1/24, and 1/25 scale for cars and trucks; 1/9 and 1/12 scales for motorcycles. 

Scale figures are often denoted by millimeter (mm) scale that developed from miniature wargames. Don’t be alarmed when you run across a figure labeled 54mm or 75mm. This ostensibly refers to the height of the figure (from the top of the head to the feet). To figure out the approximate fractional scale of a figure, divide 1,829mm (roughly 6 feet) by the figure’s millimeter scale. A 54mm figure roughly equates to 1/35 scale (actually 1/34), but could be used for 1/32 scale, too. A 25mm figure passes as 1/72 scale. 

Model railroading scales add a further twist to the story. Again, without getting into the minutiae as to why, model railroading scales are represented by letters (from smallest to largest): Z, N, TT, HO, HOn3, S, O, and G. Wouldn’t you know it, none of these scales have exact matches for popular scale model scales. However, HO (and HOn3) equals 1/87; S is 1/64 (think Hot Wheels cars); O is often said to be 1/48 scale, though it can go as large as 1/45 scale and as small as 1/50 scale (a popular die-cast vehicle scale); and, finally, G is 1/22.5 scale, generally speaking.

One last bit of advice: If you plan to build multiple models that have a relationship to each other, perhaps in a diorama, you should keep the scale constant. That means, if you have a 1/35 scale tank, then the figures should also be 1/35 scale (54mm). If not, the figures will either look unnaturally small or gargantuan in comparison to the tank. Yes, some modelers use models of different scales to cleverly force perspective and create the illusion of distance in their scenes. However, learn to walk before trying to sprint.

Where do you go from here? It’s up to you! The choice of modeling scale is entirely up to your preferences and may affect the sorts of models you tend to build. Some modelers concentrate on 1/72 scale aircraft, while others build only 1/35 scale armor. The reasons could be manifold, from range of interests to workspace and display restrictions to physical limitations due to eyesight or fine motor control. Or you may find that you like to model in a lot of different scales and a lot of different subjects. And that is totally cool with us! (Not that you asked.)

Oh! To answer the question at the top, HO is closer to 1/90 than 1/72 scale.

Want to know more about model scales? Then you definitely want to check out Getting Started in Scale Modeling and Essential Skills for Scale Modelers.