Convert a 1/8″ = 1′-0″ (1:96) scale drawing measurement to real feet and inches, or a real size to drawing inches, plus other architectural scales.
Calculator Functions
The calculator converts between a drawing and real life at 1/8 inch = 1 foot, or at another architectural scale you pick. Results come in decimals and to the nearest 1/16 inch. Select a function to open it in the calculator.
| Function | Use it when | You enter |
|---|---|---|
| Real-world size | You measured something on a plan | Drawing measurement in inches |
| Drawing measurement | You know the real size and need to draw it | Real size in feet, inches or both |
Both functions accept fractions such as 2 1/2. An optional list changes the scale from 1/16 inch to 3 inches per foot.
1/8 Inch Scale Formulas
| R | Real-world length (ft) |
| D | Length on the drawing (in) |
| SF | Scale factor: 12 ÷ the drawing inches that represent 1 foot. At 1/8 inch, 12 ÷ 0.125 = 96 [1] |
At the default scale this simplifies to R = D × 8, so a 2.5 inch wall is 20 feet long.
Drawing measurement reverses it: D = (feet × 12 + additional inches) ÷ SF. A room 10 feet 6 inches wide draws at 126 ÷ 96 = 1.3125 inches, or 1 5/16 inches.
Common architectural scales
These are the options in the scale list. The U.S. Fire Administration lists the 3/32 inch through 1 1/2 inch scales as architect scales [1].
| Scale | Ratio | Real feet per drawing inch |
|---|---|---|
| 1/16″ = 1′-0″ | 1:192 | 16 ft |
| 3/32″ = 1′-0″ | 1:128 | 10.67 ft |
| 1/8″ = 1′-0″ | 1:96 | 8 ft |
| 3/16″ = 1′-0″ | 1:64 | 5.333 ft |
| 1/4″ = 1′-0″ | 1:48 | 4 ft |
| 3/8″ = 1′-0″ | 1:32 | 2.667 ft |
| 1/2″ = 1′-0″ | 1:24 | 2 ft |
| 3/4″ = 1′-0″ | 1:16 | 1.333 ft |
| 1″ = 1′-0″ | 1:12 | 1 ft |
| 1 1/2″ = 1′-0″ | 1:8 | 0.6667 ft |
| 3″ = 1′-0″ | 1:4 | 0.3333 ft |
1/8 inch = 1 foot conversions
| Drawing measurement | Real size |
|---|---|
| 1/8 in | 1 ft |
| 1/2 in | 4 ft |
| 1 in | 8 ft |
| 2 in | 16 ft |
| 3 1/8 in | 25 ft |
| 5 1/4 in | 42 ft |
| 12 1/2 in | 100 ft |
Limits of This Estimate
- Confirm the printed scale. Copying or resizing a print can change it, and a small adjustment puts scaled lengths in doubt [1].
- Written dimensions on a plan take precedence over scaled measurements [1].
- Fractional results round to the nearest 1/16 inch, while the decimal results use the values you entered.
Sources
- U.S. Fire Administration (FEMA), Using Engineer and Architect Scales: 1/8 inch = 1 foot as a 1/96 size, the other scales, and resized prints
