A large part of an architect's job is to draw plans and/or make models of the buildings he or she is designing. All architectural plans are drawn. The models are constructed at a specific scale that depends on the size of the object to be constructed, the purposes of the plans or models and other factors. Common architectural scales range from a ratio of 1-to-4 to 1-to-128, rarely smaller, but occasionally larger.
1-4 to 1-16 Ratios Architectural Scales
Ratios of 1-to-4 to 1-to-16 is the larger end of the commonly used architectural scales. Just imagine a drawing or a model of a typical family home at a 1-4 ratio scale; that is just too large. 1-4 ratio scale drawings would be more typical for small objects, such as birdhouses or dollhouses. 1-16 ratio scale drawings would be about the largest you would typically see for single family homes, and more often 1-36 to 1-48 ratios.
1-20 to 1-64 Ratios Archtectural Scales
This range represents the most commonly used architectural scales used for drawing of plans for single-family residences or smaller commercial buildings. Ratios of 1-to-48 or 1-to-50 is a very common architectural scale for this type of project. Note that the scale notation of 1/4-inch, for example, means 1/4-inch on the drawings equals 1 foot of the actual building, or 1-48 ratio scale.
1-96 to 1-128 Ratios Architectural Scales and Higher
Larger architectural scales in the range of 1-96 to 1-128 ratios are used for commercial projects, such as larger office buildings and factories. And, occasionally, even larger scales with a 1-500 ratio or greater are used for drawings or creating models of larger factory complexes or multi-neighbourhood real estate developments.