Decimal Feet to Feet and Inches Converter

Convert decimal feet to feet and inches by multiplying the fractional part of the feet by 12. For example, 5.75 feet is 5 feet plus 0.75 × 12 inches, so it is 5 ft 9 in. This converter also accepts feet and fractional inches in the reverse direction, with selectable rounding and a copyable result.

How to use the decimal feet converter

1. Choose decimal feet or feet-and-inches input.
2. For decimal feet, enter a number such as 5.75. For the reverse conversion, enter feet and inches separately.
3. Use a fraction such as 1/2 or a mixed number such as 9 1/2 in the inches field.
4. Select the nearest fraction of an inch that matches your measurement.
5. Check the rounding change before copying a value onto a plan, cut list or order.

Decimal feet to feet and inches formula

NIST Handbook 44, Appendix C defines 12 inches per foot. Separate the whole feet from the fractional feet, then calculate inches = fractional feet × 12. In the other direction, decimal feet = feet + inches ÷ 12.

The unit definition is exact. The amount you measured may still be approximate. Selecting a finer fraction does not make an imprecise measurement more accurate; it changes how the answer is displayed.

Why 5.10 feet is not 5 feet 10 inches

A decimal point divides the unit into tenths, hundredths and smaller parts. The .10 in 5.10 ft means one tenth of a foot, which is 1.2 inches. In contrast, 5 ft 10 in means 5 + 10/12 = approximately 5.833333 feet. This distinction matters when a spreadsheet contains decimal lengths while a tape measure is marked in feet and inches.

Worked conversions

Feet and fractional inches to decimal feet

For 7 ft 3 1/2 in, the inches field is 3.5 inches. Divide by 12 and add 7: 7 + 3.5/12 = 7.291666… ft. Keep the unrounded decimal while calculating a total, then round the final measurement to the precision you intend to use.

Rounding can carry into the next foot

5.999 ft is 71.988 inches. At the nearest 1/16 inch it rounds to 72 inches, which is 6 ft 0 in. Displaying 5 ft 12 in would be an unnecessarily awkward representation of the same rounded length. The converter carries full inches into feet after rounding.

How fractional-inch rounding works

The converter multiplies total inches by the selected denominator, rounds to the nearest whole tick, and divides by that denominator. It reduces the resulting fraction, so 8/16 is displayed as 1/2. The rounding-change line is rounded inches minus original inches: a positive number increased the length and a negative number decreased it.

The rounding increments are user-selected display settings, not construction tolerances. A drawing or fabrication specification may require a different rounding convention or greater precision. Do not round each component separately if you need an accurate accumulated length.

Decimal feet, linear feet and square feet

Decimal feet describe a length using decimal notation. Linear feet are also length, but often describe the sum of many pieces or material sold by length. Square feet are area and cannot be converted into a single length without another dimension. Use the linear feet calculator to total boards or trim, or the mm-to-inches converter for metric measurements and tape-measure fractions.

The tool uses the current international-foot relationship. Legacy survey measurements are a separate context; NIST’s guidance explains the retirement of the U.S. survey foot. Enter physical lengths as nonnegative numbers and check the units in the source document before converting.

Frequently asked questions

Sources & method

• NIST Handbook 44 (2026), Appendix C — 12 inches per foot
• NIST — revised unit conversion factors and the international foot

Results are estimates for general information. Found an error? It helps everyone — see our methodology.