Architectural Scale Converter
Convert a measurement on a drawing to its real size — or a real size to what you should draw — at any metric or imperial architect’s scale. Free, no sign-up.
Real-world size at 1:100
- millimetres
- 5,000
- centimetres
- 500
- metres
- 5
- inches
- 196.85
- feet
- 16.404
Rescale a drawing
How drawing scales work
A drawing scale is a ratio between the size of something on paper and its size in reality. At 1:100, one unit on the drawing stands for 100 of the same units on site, so 1 cm on the plan is 1 m in the building. Metric scales are written as a plain ratio (1:50, 1:200). Imperial architect’s scales are written as a drawing length equal to one foot — 1/4" = 1'-0" means a quarter inch represents a foot, which is a ratio of 1:48.
To get a real size, multiply the drawing measurement by the scale’s ratio. To work out what to draw, divide the real size by the ratio. To move a drawing between scales, divide the old ratio by the new one: 1:100 to 1:50 is 100 ÷ 50 = 2, so print it at 200%.
Common architectural scales
| Scale | Ratio | Typical use |
|---|---|---|
| 1:1 | 1:1 | Full-size details and templates |
| 1:5 | 1:5 | Joinery and fixing details |
| 1:10 | 1:10 | Construction details |
| 1:20 | 1:20 | Interior elevations, wall sections |
| 1:25 | 1:25 | Room layouts and sections |
| 1:50 | 1:50 | Floor plans, sections, elevations |
| 1:75 | 1:75 | Smaller-scale plans |
| 1:100 | 1:100 | General arrangement plans and elevations |
| 1:200 | 1:200 | Building plans, small site plans |
| 1:250 | 1:250 | Site layouts |
| 1:500 | 1:500 | Site plans and block plans |
| 1:1000 | 1:1000 | Masterplans |
| 1:1250 | 1:1250 | Location plans (UK) |
| 1:2500 | 1:2500 | Location and area plans |
| 3" = 1'-0" | 1:4 | Large-scale details |
| 1-1/2" = 1'-0" | 1:8 | Details |
| 1" = 1'-0" | 1:12 | Details and enlarged plans |
| 3/4" = 1'-0" | 1:16 | Details |
| 1/2" = 1'-0" | 1:24 | Enlarged plans, interior elevations |
| 3/8" = 1'-0" | 1:32 | Interior elevations |
| 1/4" = 1'-0" | 1:48 | Residential floor plans |
| 3/16" = 1'-0" | 1:64 | Floor plans |
| 1/8" = 1'-0" | 1:96 | Commercial floor plans |
| 3/32" = 1'-0" | 1:128 | Large building plans |
| 1/16" = 1'-0" | 1:192 | Site and large building plans |
Turn the drawing into a picture
Once the plan is to scale, AI Render Studio can turn the same drawing into a photoreal view — a 3D floor plan from a 2D plan, or an exterior render from an elevation — in about 12 seconds.
Common questions
How do I convert a 1:100 drawing to real size?
Multiply the measurement on the drawing by 100. For example, 50 mm on a 1:100 plan is 5,000 mm, or 5 m, on site. The converter does this for every unit at once.
What does 1/4" = 1'-0" mean as a ratio?
A quarter inch on the drawing represents one foot (12 inches) in reality, so the ratio is 1:48. One inch on the drawing equals four feet.
How do I rescale a drawing from 1:100 to 1:50?
Divide the old scale’s denominator by the new one: 100 ÷ 50 = 2, so enlarge the drawing to 200%. Going from 1:50 to 1:100 means printing at 50%.
Which scale is used for floor plans?
In metric countries, floor plans are usually drawn at 1:50 or 1:100; in the US, residential plans are typically 1/4" = 1'-0" (1:48) and larger buildings 1/8" = 1'-0" (1:96).
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