What Is A Scale Drawing

Scaling is a drawing method used to enlarge or reduce a drawing in size while keeping the proportions of the drawing the same. Scales are generally expressed as ratios and the most common scales used in furniture drawing are 1:1, 1:2, 1:5, and 1:10 for reducing and possibly 2:1 for enlarging.

Scaling is used to either:

reduce the drawing in size so that it will fit onto the page, or

enlarge the drawing in size so that all required details are clearly visible.

Drawings can be scaled up or down using either a calculator or a scale rule.

To scale a drawing using a calculator:

divide the measurement by the scale if you want to reduce the drawing in size, or
multiply the measurement by the scale if you want to increase it in size.

Example 1: Scaling down

A 50mm line is to be drawn at a scale of 1:5 (ie 5 times less than its original size). The measurement 50mm is divided by 5 to give 10mm. A 10mm line is drawn.

A 50mm line is to be drawn at a scale of 1:2. The measurement 50mm is divided by 2 to give 25mm. A 25mm line is drawn.

Example 2: Scaling up

A 50mm line is to be drawn at a scale of 5:1 (ie 5 times more than its original size). The measurement 50mm is multiplied by 5 to give 250mm. A 250mm line is drawn.

A 50mm line is to be drawn at a scale of 2:1. The measurement 50mm is multiplied by 2 to give 100mm. A 100mm line is drawn.

To scale a drawing using a scale rule:

Scale rules allow us to directly set out measurements onto a drawing without having to convert them to their scaled sizes by using a calculator first.

The whole process is made easier because these conversions are already made for us. On a scale rule which has divisions of 1:5, each division represents 5mm and the measurements on the rule indicate this.

Scale rulers.

On a scale rule which has divisions of 1:10 each division represents 10mm and the measurements on the rule indicate this.

Remember icon

Even though the drawing itself may be reduced in size or drawn at an enlarged size on the page, all dimensioning on the drawing should reflect the correct sizes of the item being drawn.

This is an example of a scaled drawing. Notice that the elevation is drawn at a scale of 1:10.

Included in the drawing is detail A, and this is drawn additionally at a scale of 1:1, or full size.

A scaled drawing.