Drawing scale converter

How it works

A drawing at 1:100 shows a real length one hundred times smaller. Enter the physical length in metres and the scale denominator; the result is the length to draw in millimetres. A 10 m wall becomes 100 mm at 1:100, 200 mm at 1:50 and 50 mm at 1:200.

Worked example

To read a printed drawing in the other direction, multiply measured millimetres by the denominator and divide by 1,000. A line measuring 25 mm on a 1:100 drawing represents 2.5 m. Check a known dimension first: a PDF printed with “fit to page” may no longer retain its stated scale.

Before using the result

Use the result for diagrams and early layout checks. CAD model space generally stores real dimensions; its drawing or viewport scale controls the printed representation. Changing units and changing scale are separate operations.

More useful references

Square metres and square feet converter

Floor-area ratio calculator

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