Scale Calculator
Convert between drawing and real sizes at any scale (1:48, 1/4" = 1', 1" = 30'), or find the scale factor of a drawing or model.
Change the values and press Calculate to work out your own figures.
Real size to scale size
Enter the scale and the real size.
Show the working
- scale size = real size ÷ scale factor
- scale factor 1:8
Scale size to real size
Enter the scale and the drawing's size.
Show the working
- real size = scale size × scale factor
- scale factor 1:8
Find the scale factor
Enter the real size and the scale size.
Show the working
- scale factor = real size ÷ scale size
- 24
How to use it
Enter the scale and the real size. Enter the scale and the drawing's size. Enter the real size and the scale size.
Lengths can be decimals, fractions or tape entries such as 12' 6 1/2" (in feet or inches). Prices are optional.
Key facts
scale size = real size ÷ scale factor real size = scale size × scale factor scale factor = real size ÷ scale size
Architectural and engineering scales
1/4" = 1' means a quarter inch on the drawing is a foot in reality: 12 ÷ 0.25 = 1:48. Engineering scales such as 1" = 30' are 1:360.
Architectural scales
| Scale | Ratio |
|---|---|
| 1/16" = 1' | 1:192 |
| 3/32" = 1' | 1:128 |
| 1/8" = 1' | 1:96 |
| 3/16" = 1' | 1:64 |
| 1/4" = 1' | 1:48 |
| 3/8" = 1' | 1:32 |
| 1/2" = 1' | 1:24 |
| 3/4" = 1' | 1:16 |
| 1" = 1' | 1:12 |
| 1 1/2" = 1' | 1:8 |
| 3" = 1' | 1:4 |
Engineering scales
| Scale | Ratio |
|---|---|
| 1" = 10' | 1:120 |
| 1" = 20' | 1:240 |
| 1" = 30' | 1:360 |
| 1" = 40' | 1:480 |
| 1" = 50' | 1:600 |
| 1" = 60' | 1:720 |
| 1" = 70' | 1:840 |
| 1" = 80' | 1:960 |
| 1" = 90' | 1:1,080 |
| 1" = 100' | 1:1,200 |
Questions
What is 1/4 inch = 1 foot as a ratio?
1:48.
At 1:8, how big is 32 ft?
4 ft.
Formulas
scale size = real size ÷ scale factor real size = scale size × scale factor scale factor = real size ÷ scale size
Sources
Limitations
- Material densities are typical values (the midpoint of the commonly published range); real loads vary with moisture, grading and compaction, so check with your supplier or type in their density.
- Tank results are the geometric volume; real tanks have wall thickness and fittings.