Blueprint drawings are typically drawn in
- 1:20, 1:50 or 1:100 (SI-units)
- 1/4" or 1/8" (Imperial units, US)
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
Component Drawings, Assembly
Floor Plans, General Arrangement (GA)
Location Plot Plans
Location Plat Plans
Block Plan, City Maps and larger
Ordnance Survey Maps
The SI-system, unit converters, physical constants, drawing scales and more.
2D and 3D engineering drawing tools.
Online app that can be used to make an exact plot of a surveyed area - like a room, a property or any 2D shape.
Letters commonly used to differentiate blueprint drawings.
Convert builder's measurements to surveyor's measurements.
Typical tolerances for floors, walls, columns and more.
Standard drawing sheets layouts.
Standard metric drawing sheet sizes.
Golden Section also called the Golden Mean.
Draw HVAC diagrams online with this Google Drive drawing tool.
Convert lengths areas between different mapping scales.
Draw P&ID diagrams online in the browser with Google Docs.
ISO vs. U.S. and Canadian drawing sheets.
ISO 216 A, B and C drawing series - dimensions of regular, oversized and envelope sheets.
Office paper sizes as Letter, Legal, Tabloid and more.
Printing and drawing papers sizes.
The relative scale of objects.
US architectural drawing sizes and formats.
US engineering drawing sizes based on ANSI/ASME Y14.1.