How do I find the scale of an unknown model?

Identify the real-world subject, look up a key dimension (e.g. overall length or wingspan), measure the same dimension on the model in the same units, then divide the real measurement by the model measurement. This calculator does that maths and finds the closest standard scale.

What if the ratio does not match any standard scale?

Many vintage models, souvenirs and toy models are made to non-standard scales for commercial reasons like fitting a standard box size. The calculator will tell you the exact ratio and the nearest standard scale.

Should I measure in millimetres or inches?

Either works as long as both measurements use the same unit. Millimetres are more precise for small models. The ratio is dimensionless so the units cancel out.

ModelCalcs

Scale Ratio Calculator — Find the Scale

Enter a known real-world dimension and its model equivalent to determine the scale ratio.

Real-World Size

The known real-world dimension

Model Size

The measured model dimension

How We Calculate This

The scale ratio is simply the real-world dimension divided by the model dimension.

Formula

Scale ratio = Real size ÷ Model size

Example: Real aircraft wingspan 11,000mm, model measures 152mm. Ratio = 11,000 ÷ 152 = 72.4, so the model is approximately 1:72.

Frequently Asked Questions

Related Calculators

Scale Calculator

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Real to Scale Converter

Convert a real-world measurement down to your chosen model scale.

Scale to Real Converter

Convert a model measurement back up to find the real-world equivalent.

Mixed Scale Calculator

Convert a measurement from one model scale to another without going back to real size.

Scale Speed Calculator

Calculate the correct scale speed so your model moves at a realistic pace.

Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.