How to use it
There are four boxes for the same length. Type in any one of them and the other three show the conversion, with the fraction rounded to the nearest 1/16 inch unless you change it.
- Decimal ft takes a plain number:
9.9063means 9.9063 feet. - Feet-inch takes a tape-measure dimension such as
9' 10 7/8". - Inches takes a plain number or a fraction:
118.875or118 7/8. - Metric mm takes millimeters:
3019.4.
Worked example
A civil drawing gives a dimension of 9.9063 ft. Keep the 9 whole feet. Multiply the rest by 12: 0.9063 × 12 = 10.8756 inches, so 10 whole inches. Multiply what is left by 16: 0.8756 × 16 = 14.01, which is 14 sixteenths, or 7/8. The answer is ≈ 9' 10 7/8".
Going the other way, 7' 6 3/4" is 6.75 inches past 7 feet. Divide by 12: 6.75 ÷ 12 = 0.5625, so the length is 7.5625 ft.
Tenths of a foot in inches
Survey and civil drawings are dimensioned in tenths and hundredths of a foot. A tenth of a foot is 1.2 inches, not 1 inch.
| Decimal feet | Inches | Nearest 1/16" |
|---|---|---|
| 0.1 ft | 1.2 in | ≈ 1 3/16" |
| 0.2 ft | 2.4 in | ≈ 2 3/8" |
| 0.3 ft | 3.6 in | ≈ 3 5/8" |
| 0.4 ft | 4.8 in | ≈ 4 13/16" |
| 0.5 ft | 6 in | 6" |
| 0.6 ft | 7.2 in | ≈ 7 3/16" |
| 0.7 ft | 8.4 in | ≈ 8 3/8" |
| 0.8 ft | 9.6 in | ≈ 9 5/8" |
| 0.9 ft | 10.8 in | ≈ 10 13/16" |
Inches as decimal feet
| Inches | Decimal feet |
|---|---|
| 1" | 0.0833 ft |
| 2" | 0.1667 ft |
| 3" | 0.25 ft |
| 4" | 0.3333 ft |
| 5" | 0.4167 ft |
| 6" | 0.5 ft |
| 7" | 0.5833 ft |
| 8" | 0.6667 ft |
| 9" | 0.75 ft |
| 10" | 0.8333 ft |
| 11" | 0.9167 ft |
Questions
How do I convert decimal feet to feet and inches?
Keep the whole number as feet, then multiply the decimal part by 12 to get inches. For 9.5 feet, 0.5 × 12 is 6, so the answer is 9' 6". If the inches come out with a decimal, multiply that decimal by 16 to get sixteenths of an inch.
How do I convert feet and inches to decimal feet?
Divide the inches by 12 and add the result to the feet. 7' 6 3/4" is 7 feet plus 6.75 inches, and 6.75 ÷ 12 is 0.5625, so it is 7.5625 feet.
How many inches is a tenth of a foot?
A tenth of a foot is 1.2 inches, which is about 1 3/16" on a tape measure. A hundredth of a foot is 0.12 inches, close to 1/8 inch.
Why does the answer show ≈?
Most decimals do not land exactly on a sixteenth of an inch, so the fraction is rounded to the nearest 1/16 and marked with ≈. The decimal inches in the results list are not rounded. You can round to anything from 1/2 down to 1/64.
Can I type a unit in the box?
Yes. A plain number takes the unit of the box it is in. If you type a unit, that wins: 30" typed in the decimal feet box is still 30 inches.
More calculators
- Feet & inches calculatorAdd, subtract, multiply and divide feet, inches and fractions. Free, nothing to install.
- Roof pitch & rafter length calculatorEnter any two of pitch, rise, run and diagonal. The other two fill in.
- Stair calculatorEnter the floor-to-floor rise to get risers, treads, total run and stringer length.
- Circle & arc calculatorEnter a diameter for circumference and area. Add an angle for arc length and chord.
- Square footage & volume calculatorEnter length and width for area. Add a height for volume, cubic yards and wall area.
- Stud & on-center spacing calculatorEnter a length and a spacing to get the member count, the last bay and the equal spacing.
- Concrete calculatorPick slab, footing, wall or round column, type the size in feet and inches, and get cubic yards and bags.
- Slope converterType a slope as inches per foot, percent, degrees or a ratio. The other three fill in.
- Gravel, sand, soil & mulch calculatorPick the material, type the length, width and depth, and get cubic yards and approximate tons.
- Drawing scale calculatorEnter a scale and a length to convert it, or a drawn length and its real size to find the scale.
Reference finders
- DSA forms & publications finderType a topic or a number, or paste a plan check comment, and see which DSA documents to open.
- OSHPD / HCAI CAN, PIN & forms finderType a topic or a number, or paste a plan review comment, and see which HCAI documents to open.