Architects design buildings and structures and then draw them on plans in two- or three-dimensional perspective. It would be impractical to draw full-size drawings of large objects, so architects use architectural scales to reduce their drawings to a manageable size or scale. The scale architects use will depend on the size of the object. For instance, you will need a different scale to draw an engine than a hospital. To convert architectural scales to the life-size of an object you need a tool aptly called a scale.
Select the correct tool. There are two types of scales: architectural scales and engineer scales. Architects use architectural scales, which represent different ratios in feet and inches. Engineer scales represent decimalised fractions of an inch and allow for greater precision than architectural scales.
Check the scale the architect used on the plan and use the same scale on the architect's scale ruler. A typical architectural scales is 1/4 inch = 1 foot, 0 inch (1/48 ratio), according to the U.S. Fire Administration. That scale means that every quarter of an inch on the drawing is equal to 1 foot in the real world, or in other words 48 times the size represented on the drawing.
Choose the object for which you want to convert the scales. Allign the "0" marker on your scale ruler with one end of the object. Find the object's end point and check what number it corresponds with on the scale ruler. That number is the size of the object when built.
Always compare your scale ruler with the selected scale of the plan to check it is correct. Sometimes plotters, printers for large plans, might adjust the size of the plan to size of the paper and misrepresent the scale.