Architectural scale converter

How to use the Scale Converter

Convert measurements between a drawing and real size at any architectural scale, metric or imperial, find an unknown scale, and work out the new scale after resizing a sheet.

1. Choose what you want to do: drawing to real, real to drawing, change sheet or find scale.
2. Pick the drawing scale, such as 1:100 or 1/4" = 1'-0".
3. Enter the length you measured or the real length you need to draw.
4. Read the converted length, with the scale factor shown.

Worked example

At 1:100, 25 mm on the drawing is 2,500 mm (2.5 m) in reality. An A1 drawing at 1:100 printed on A3 becomes about 1:200, because A3 is half the width of A1. If 50 mm on a print measures 5 m on site, the scale is 1:100.

Good to know

• Imperial scales convert to ratios: 1/4" = 1'-0" is 1:48 and 1/8" = 1'-0" is 1:96.
• A printed drawing is only to scale when printed at 100% (actual size), not "fit to page".
• Add a scale bar to drawings so they stay readable when resized.