Architectural scale converter
Turn a length measured on a drawing into real size, or a real size into drawing length, at any architectural, engineering or metric scale. Free, no sign-up.
Free tool
Convert a length
Real-world length at 1:48
14' 0" (4.267 m)
Rescale a print
What percentage to print at
To print or copy a drawing at a different scale, pick the scale it is at now and the one you need.
Print or copy at
200%
How it works
How to convert a drawing scale
- 1
Pick the drawing's scale
Read it from the title block or under the view title, for example 1/4" = 1'-0" or 1:100. Engineering site plans use 1" = 20' and similar.
- 2
Measure on the sheet
Measure the line on the printed sheet with a rule, in inches or millimetres, and enter it. Use a printed sheet that was not resized to fit the paper.
- 3
Read the real size
The converter multiplies by the scale ratio and shows the result in feet and inches and in metres. Switch direction to work out how long a real length will draw.
- Real size
- drawing length × scale ratio
- Drawing length
- real size ÷ scale ratio
- Ratio of an architectural scale
- 12 ÷ inches per foot (1/4" = 1' gives 12 ÷ 0.25 = 48, so 1:48)
- Copier percentage
- current ratio ÷ wanted ratio × 100 (1:100 to 1:50 is 200%)
Reference
Common drawing scales
Every scale on the converter, with its ratio and what one inch or ten millimetres on the sheet stands for.
| Scale | Ratio | 1 inch on the sheet |
|---|---|---|
| 1/16" = 1' | 1:192 | 16' |
| 1/8" = 1' | 1:96 | 8' |
| 3/16" = 1' | 1:64 | 5' 4" |
| 1/4" = 1' | 1:48 | 4' |
| 3/8" = 1' | 1:32 | 2' 8" |
| 1/2" = 1' | 1:24 | 2' |
| 3/4" = 1' | 1:16 | 1' 4" |
| 1" = 1' | 1:12 | 1' |
| 1-1/2" = 1' | 1:8 | 8" |
| 3" = 1' | 1:4 | 4" |
| 1" = 10' | 1:120 | 10' |
| 1" = 20' | 1:240 | 20' |
| 1" = 30' | 1:360 | 30' |
| 1" = 40' | 1:480 | 40' |
| 1" = 50' | 1:600 | 50' |
| 1" = 60' | 1:720 | 60' |
| 1" = 100' | 1:1200 | 100' |
| Scale | 10 mm on the sheet |
|---|---|
| 1:5 | 5 cm |
| 1:10 | 10 cm |
| 1:20 | 20 cm |
| 1:25 | 25 cm |
| 1:50 | 50 cm |
| 1:100 | 1 m |
| 1:200 | 2 m |
| 1:250 | 2.5 m |
| 1:500 | 5 m |
| 1:1000 | 10 m |
| 1:2500 | 25 m |
Skip the ruler
Measure the PDF itself
On a PDF there is no need to print and convert. Set the scale once in ContractorCounter and every length, area and count reads in real units on the sheet: setting the drawing scale shows how, and the free PDF measuring tool lets you try it on your own drawing with a free account and no card. For whole-job quantities, see construction takeoff software.
Drawing scale questions
How do you convert a drawing scale to real size?
Multiply the length you measure on the drawing by the scale ratio. At 1/4" = 1'-0" the ratio is 1:48, so 3 1/2 inches on the sheet is 168 inches, or 14 feet. At 1:100, 10 mm on the sheet is 1,000 mm, or 1 metre.
What ratio is 1/4 inch scale?
1:48. A quarter inch on the drawing stands for 12 inches, and 12 divided by 0.25 is 48. Likewise 1/8" = 1' is 1:96, 1/2" = 1' is 1:24 and 3/16" = 1' is 1:64.
Is 1:50 bigger than 1:100?
Yes. A drawing at 1:50 shows everything twice as large as the same drawing at 1:100, so it fits less of the building on the sheet and shows more detail.
What percentage do I print at to change the scale?
Divide the current ratio by the one you want and multiply by 100. To turn a 1:100 drawing into 1:50, print at 200%. To turn 1/4" = 1' into 1/8" = 1', print at 50%.
How do I find the scale of a drawing with no scale shown?
Find a dimension written on the drawing, such as a labelled wall or door width, and measure that line on the sheet. The real length divided by the measured length is the scale ratio. Check it against a second dimension before relying on it.
Why do my measurements come out wrong on a printed PDF?
Usually because the PDF was printed with Fit to page or Shrink to fit, which changes the scale. Print at 100% or Actual size, or check the print against the drawing's scale bar or a written dimension first.
What is the difference between an architectural and an engineering scale?
Architectural scales give a fraction of an inch per foot, such as 1/4" = 1', and are used for buildings. Engineering scales give whole feet per inch, such as 1" = 20', and are used for site and civil plans. Both reduce to a ratio: 1:48 and 1:240 in those examples.
