🏗️ Scale model
Scale Model Converter
Turn a real-world measurement into the size it becomes on a model at any hobby scale, or move a dimension from one scale to another. Enter a value and press Convert.
About the scale model converter
A modelling scale is a ratio. At 1:72 the model is 72 times smaller than the real thing, so a 20 metre aircraft becomes 20,000 ÷ 72 = 278 mm long. Every value here is a plain length, so the answer is in whatever unit you typed — convert millimetres, centimetres, inches or metres freely.
Pick 1:1 (real size) to work against the real object: 100 mm at 1:72 becomes 1:1 real size, telling you the original would be 7,200 mm — 7.2 metres.
Popular hobby scales
| Scale | Divisor | Typical subject |
|---|---|---|
| 1:12 | 12 | Dolls houses, large figures, engines |
| 1:18 | 18 | Diecast cars, action figures |
| 1:24 | 24 | Model cars, trucks, aircraft |
| 1:35 | 35 | Military vehicles and armour |
| 1:43 | 43 | Collector cars, railways (Europe) |
| 1:48 | 48 | Aircraft, O scale railways |
| 1:64 | 64 | Diecast cars, S scale railways |
| 1:72 | 72 | Aircraft, AFVs, ships |
| 1:87 | 87 | HO scale railways |
| 1:144 | 144 | Airliners, armour, wargames |
| 1:350 | 350 | Ship models |
| 1:700 | 700 | Waterline ship models |
How to convert between scales
Real size = model size × scale divisor. Model size = real size ÷ scale divisor. To jump straight from one scale to another, multiply by the first divisor and divide by the second: a 100 mm part at 1:72 would be 100 × 72 ÷ 48 = 150 mm at 1:48.
Worked examples
- A 1:72 Spitfire with a 70 mm wingspan represents 70 × 72 = 5,040 mm, or 5.04 m — the real aircraft spans about 11.2 m over the full wing, so a 70 mm span would be a clipped wing.
- A 6 m truck at 1:24 becomes 250 mm long on the shelf.
- Converting a 1:35 figure part of 30 mm to 1:72 gives 30 × 35 ÷ 72 = 14.6 mm, which is why smaller scales need separate kits rather than scaled parts.
- Multiply by 25.4 to move inches to millimetres: 1.5 in at 1:48 is 38.1 mm.
Working from a drawing to your scale
Scratch-building usually starts with a plan drawn at a different scale from the model. The conversion is a ratio of ratios: multiply every dimension on the drawing by the drawing's scale and divide by the model's scale. A plan at 1:100 used for a 1:72 model is enlarged by 100 ÷ 72 = 1.389, so a 40 mm dimension becomes 55.6 mm on the model.
Photocopiers and printers express the same adjustment as a percentage. Going from 1:72 to 1:48 means enlarging to 150 percent; going from 1:48 down to 1:72 means reducing to 66.7 percent. Print, measure a known dimension with a rule, and correct the percentage once before printing the whole sheet — paper feed distorts by a percent or two, which is enough to throw off a wing joint.
Materials have their own units. Sheet styrene is sold by thickness in thousandths of an inch (0.040 in is about 1 mm) and in millimetres in Europe, while brass tube and rod are usually millimetre outside diameter with a wall thickness in millimetres. Convert the material to the model's scale as well as the drawing: a 1 mm panel at 1:72 represents 72 mm of real plate, thicker than most aircraft skin, and should be sanded thinner or replaced with foil.
Frequently asked questions
Common mistakes to avoid
- Dividing when you should multiply. Real objects are always larger, so real ÷ scale = model.
- Mixing scales within a project. A 1:72 accessory beside a 1:48 vehicle looks obviously wrong.
- Forgetting that volume scales with the cube — half the linear size is one eighth the volume and weight.
- Assuming a "28 mm" miniature is 1:56. The millimetre figure describes a typical human figure's height, not a formal ratio.