Drawing Scales
Blueprint drawings are typically drawn in
- 1:20, 1:50 or 1:100 (SI-units)
or
- 1/4" or 1/8" (Imperial units, US)
scales.
SI-Units
To scale a SI-drawing
- multiply the measurement on the drawing with the denominator
where the denominator is the number after the colon.
Example - Blueprint Drawing Scale 1:50
An actual length of 1 cm is measured on a 1:50 blueprint floor plan. The physical length can be calculated as
(1 cm) 50 = 50 cm
Imperial Units - US
A 1/4" scale means that each 1/4" (inch) on the plan counts for 1' (feet) of actual physical length.
To scale a blueprint in imperial units to actual feet
- multiply the measurement on the drawing (in inches decimal equivalent) with the denominator
where the denominator is the bottom number.
Example - Blueprint Drawing Scale 1/4"
An actual length is measured to 1-3/8" on a 1/4" blueprint floor plan. The physical length can be calculated as
(1-3/8 inch) 4 = (1.375 inch) 4
= 5.5 feet
= 5' 6"
Commonly Used Drawing Scales
Details
- 1:1
- 1:5
- 1:10
- 1:20
Component Drawings, Assembly
- 1:20
- 1:10
- 1:5
Floor Plans, General Arrangement (GA)
- 1:40
- 1:50
Location Plot Plans
- 1:80
- 1:100
- 1:200
Location Plat Plans
- 1:500
Block Plan, City Maps and larger
- 1:1000
- 1:1250
- 1:2500
Ordnance Survey Maps
- 1:100000
- 1:50000
- 1:25000
- 1:10000
Related Topics
• Basics
The SI-system, unit converters, physical constants, drawing scales and more.
• Drawing Tools
2D and 3D engineering drawing tools.
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