ModelCalcs.uk
Scale Ratio Calculator — Find the Scale
Enter a known real-world dimension and its model equivalent to determine the scale ratio.
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
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.
Many vintage models, souvenirs and toy models are made to non-standard scales for commercial reasons like fitting a standard box size. The calculator always shows the exact ratio. If the nearest standard scale is further away than the Match Tolerance (default 5, adjustable under Advanced Options), it reports "Non-standard scale" rather than forcing a misleading match.
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.
Related Calculators
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Mixed Scale Calculator
Convert a measurement from one model scale to another without going back to real size.
Scale Calculator
Convert any measurement between real world and model scale. Supports all common scales.
Real to Scale Converter
Convert a real-world measurement down to your chosen model scale.
Scale Speed Calculator
Calculate the correct scale speed so your model moves at a realistic pace.
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Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.