How to convert one model scale to another
Resize plans and parts from one existing model scale to another.
How it works
A 100 mm part at 1:72 becomes 150 mm at 1:48.
Checked example
Moving from 1:72 to 1:48 enlarges a model; the reverse reduces it.
Workshop notes
Use the actual 1:N ratio when a hobby scale name varies by region.
Read the denominators correctly
A 1:48 model is larger than a 1:72 model because each model unit represents fewer real units. When moving from 1:72 to 1:48, the part must grow; the source denominator divided by the target denominator is greater than one.
Check an enlargement example
A 120 mm wall at 1:72 converted to 1:48 is 120 × 72 ÷ 48 = 180 mm. Its width and height must receive the same factor. Uniform conversion preserves proportions, while changing only one axis distorts the project.
Check a reduction example
A 6-inch plan dimension at 1:12 converted to 1:24 becomes 6 × 12 ÷ 24 = 3 inches. The target denominator doubled, so every linear dimension is halved. Area becomes one quarter, but that area change is not entered into the linear formula.
Separate scale from fit
A correct geometric conversion does not guarantee that tabs, hinges, joints, track parts, or printed walls will still work. Review material thickness and mechanical clearances after resizing, especially when reducing a design.
Frequently asked questions
Why does a smaller denominator make a larger model?
The denominator states how many real units one model unit represents. Fewer real units per model unit means the model is physically larger.
What percentage converts 1:72 to 1:48?
72 ÷ 48 × 100 = 150 percent.
Can I convert a printed plan this way?
Yes, if the plan was printed without distortion. Verify one marked dimension before trusting the whole sheet.
Do I scale material thickness too?
Geometrically yes, but practical materials and minimum printable thickness may require adjustment.