AutoCAD Scale Factor - Architecture Dictionary

AutoCAD Scale Factors

Use this scale factor chart to help you find a usable conversion factor for your CAD drawings 📐

Architectural

Drawing ScaleScale FactorViewport ScaleDecimal Scale
1/16" = 1'-0"1921/192 xp0.0625" = 1'-0"
3/32" = 1'-0"1281/128 xp0.09375" = 1'-0"
1/8" = 1'-0"961/96 xp0.125" = 1'-0"
3/16" = 1'-0"641/64 xp0.1875" = 1'-0"
1/4" = 1'-0"481/48 xp0.25" = 1'-0"
3/8" = 1'-0"321/32 xp0.375" = 1'-0"
1/2" = 1'-0"241/24 xp0.5" = 1'-0"
3/4" = 1'-0"161/16 xp0.75" = 1'-0"
1" = 1'-0"121/12 xp1" = 1'-0"
1 1/2" = 1'-0"81/8 xp1.5" = 1'-0"
3" = 1'-0"41/4 xp3" = 1'-0"

To convert an architectural drawing scale to a scale factor:

Select the desired scale, then invert the fraction and multiply by 12.

For example, if you choose 1/8" = 1'-0"

• Invert the 1/8 to get 8/1

• Multiply 8/1 by 12

• 8/1 x 12 = 96

• Scale Factor = 96

Engineering

Drawing ScaleScale FactorViewport Scale
1" = 10'-0"1201/120 xp
1" = 20'-0"2401/240 xp
1" = 30'-0"3601/360 xp
1" = 40'-0"4801/480 xp
1" = 50'-0"6001/600 xp
1" = 60'-0"7201/720 xp
1" = 70'-0"8401/840 xp
1" = 80'-0"9601/960 xp
1" = 90'-0"10801/1080 xp
1" = 100'-0"12001/1200 xp

To convert an engineering drawing scale to a scale factor:

Select the desired scale, then multiply the feet by 12.

For example, if you choose 1" = 20'

• Multiply 20 by 12

• 20 x 12 = 240

• Scale Factor = 240

Beginner's guide

Understanding AutoCAD Scale Factors: A Beginner's Guide

AutoCAD, an industry-standard computer-aided design (CAD) software, uses scale factors to represent real-world dimensions accurately in a digital format. In the realm of design and engineering, scale factors are indispensable for ensuring the precision and accuracy of your drawings.

What is a Scale Factor?

A scale factor in AutoCAD is the ratio between the size of the object in the model space (actual size) to the size of the object as displayed in the layout view or paper space (printed size). Essentially, it's the method by which a real-world object is proportionally scaled down or up to fit on a sheet of paper or a digital workspace.

For example, if you're creating a drawing of a building that is 100 feet tall, you can't make your drawing 100 feet tall. Instead, you might use a scale factor that allows one inch on the paper to represent ten feet of the actual building.

Architectural vs. Engineering Scale Factors

Scale factors can be broadly classified into architectural scales and engineering scales:

Architectural Scales: Typically used in the field of architecture and interior design, architectural scales are expressed in feet and inches, and commonly use ratios like 1/4" = 1' or 3/8" = 1', etc.

Engineering Scales: Used in engineering and technical disciplines, these scales are often based on decimal ratios, such as 1:10, 1:20, 1:100, etc.

Importance of Scale Factors in AutoCAD

Scale factors are pivotal to the integrity of your design. They allow your drawing to accurately represent the actual size of the object, ensuring that every element of your design — from a tiny window detail to the overall layout of a building — is proportionally accurate.

By understanding and correctly using scale factors in AutoCAD, you can ensure that your designs can be understood and implemented accurately by everyone involved in a project — from fellow designers and architects to builders on a construction site.