Drawing Scales

Tool for calculating actual dimensions from blueprint drawings using standard drawing scales (SI-units 1:20, 1:50, 1:100 or Imperial units 1/4", 1/8")

Drawing Scales

Blueprint drawings are typically drawn in standard scales:

SI-Units

  • 1:20, 1:50, or 1:100

To scale a SI-drawing, multiply the measurement on the drawing with the denominator.

Imperial Units (US)

  • 1/4" or 1/8"

To scale a blueprint in imperial units, multiply the measurement on the drawing (in inches) with the denominator.

Commonly Used Drawing Scales

CategoryScales
Details1:1, 1:5, 1:10, 1:20
Component Drawings, Assembly1:20, 1:10, 1:5
Floor Plans, GA1:40, 1:50
Location Plot Plans1:80, 1:100, 1:200
Location Plat Plans1:500
Block Plan, City Maps1:1000, 1:1250, 1:2500
Ordnance Survey Maps1:100000, 1:50000, 1:25000, 1:10000
Calculator

Inputs

Results

Actual Physical Length-- cm
Calculator

Inputs

Results

Actual Physical Length-- feet
Scale TypeDrawing Scales
Details1:1, 1:5, 1:10, 1:20
Component Drawings, Assembly1:20, 1:10, 1:5
Floor Plans, General Arrangement (GA)1:40, 1:50
Location Plot Plans1:80, 1:100, 1:200
Location Plat Plans1:500
Block Plan, City Maps and larger1:1000, 1:1250, 1:2500
Ordnance Survey Maps1:100000, 1:50000, 1:25000, 1:10000