Decimal Feet vs. Feet and Inches
Decimal feet uses base ten, while feet-and-inches uses 12 inches per foot. Multiply the decimal part of a foot by 12 to obtain inches.
Why the notations differ
A value of 5.5 ft means five whole feet plus half of a foot. Half of 12 inches is 6 inches, so 5.5 ft equals 5 ft 6 in—not 5 ft 5 in.
Decimal feet to feet and inches
Keep the whole-number feet. Multiply the decimal part by 12. If the inch result has a decimal, convert that remainder to the fractional or decimal precision required.
| Decimal feet | Calculation | Feet and inches |
|---|---|---|
| 5.25 ft | 0.25 × 12 = 3 | 5 ft 3 in |
| 5.5 ft | 0.5 × 12 = 6 | 5 ft 6 in |
| 5.75 ft | 0.75 × 12 = 9 | 5 ft 9 in |
Feet and inches to decimal feet
Divide the inches by 12 and add the result to the whole feet. For example, 5 ft 3 in becomes 5 + 3/12 = 5.25 ft.
- Normalize 12 or more inches into another foot.
- State the notation explicitly on drawings and data fields.
- Do not place a decimal point between feet and inches as a separator.
Questions about this topic
What is 6.2 feet in feet and inches?
The decimal part is 0.2 foot. Multiplying by 12 gives 2.4 inches, so the value is 6 feet 2.4 inches.
Is 5 feet 10 inches written as 5.10 feet?
No. In decimal feet it is 5 + 10/12, or approximately 5.8333 feet.