Feet-and-inches notation and fractional inches are two ways of writing the same imperial lengths, and each suits a different workflow. A measurement such as 68 inches can be written as 5 ft 8 in for a person’s height, as 5.6667 ft for a spreadsheet estimate, or rounded onto a ruler grid for a shop drawing — and those are not interchangeable without arithmetic. The feet and inches calculator reduces mixed notation to one unambiguous value: total inches, decimal feet, or meters. The inches to fraction calculator takes a decimal inch and rounds it onto the fraction grid of a tape measure or drawing. The choice is about how the dimension needs to be written next.
What each calculator does
The feet and inches calculator accepts feet and inches, including decimals, and works through total inches: 12 times feet plus inches. It reports decimal feet, total inches, meters, and a normalized mixed result. The default 5 ft 8 in becomes 68 total inches, 5.6667 ft, 1.7272 m, and 5 ft 8 in. It accepts unusual entries such as 4 ft 15 in, treating them as 63 total inches and normalizing to 5 ft 3 in.
The inches to fraction calculator rounds a decimal inch value to the nearest fraction at a denominator you select, from 2 through 128. It separates whole inches from the remainder, multiplies the remainder by the denominator, rounds to the nearest numerator, carries when the numerator reaches the denominator, and reduces by the greatest common divisor. The default 2.625 in at 1/16-inch precision rounds to 2 5/8 in with a rounding difference of 0 in; the page’s follow-up, 3.2 in at 1/16, becomes 3 3/16 in with a rounded decimal of 3.1875 in and an error of −0.0125 in.
Side-by-side comparison
| Feet and inches calculator | Inches to fraction calculator | |
|---|---|---|
| Input | Feet and inches, decimal allowed | Single decimal inch value |
| Primary output | Decimal feet, total inches, meters, normalized ft-in | Fraction on a chosen ruler grid, rounded decimal, error |
| Formula | total inches = 12 × ft + in; decimal ft = total/12; m = total × 0.0254 | numerator = round(remainder × denominator), reduced |
| Notation produced | Decimal and mixed | Fractional |
| Example | 5 ft 8 in → 5.6667 ft, 68 in, 1.7272 m | 2.625 in at 1/16 → 2 5/8 in |
| Best for | Arithmetic, records, metrics, and mixed measurements | Cut lists, plans, and ruler-mark precision |
When to use which
Use the feet and inches calculator when the source is mixed notation or when the result must feed further math: multiplying by a price per foot, comparing dimensions in a spreadsheet, or converting to meters for a metric drawing. Decimal feet and total inches both work directly in calculations; normalized ft-in is for labels.
Use the inches to fraction calculator when a decimal inch value must be expressed on the marks of an actual tool or plan: a tape measure in sixteenths, a shop drawing in thirty-seconds, or a cabinet part that will be cut from a rule. Pick the coarsest denominator that still meets your tolerance — an eighth-inch layout versus a sixty-fourth-inch trim cut. The two tools are also a pipeline: the inches to fraction page recommends converting mixed measurements to total inches first, then rounding the decimal value.
Limits and disclaimer
Both calculators perform exact arithmetic on the values you enter — the feet-and-inches math rests on the exact 12-inch foot and 0.0254-meter inch, and the fraction rounding reports its own error so you can see what precision was lost. Neither adds measurement accuracy. Do not write 5 ft 8 in as 5.8 ft — decimal feet use tenths of a foot, not inches. Do not assume every decimal has a short exact fraction; 0.1 in lands on no common denominator, so the result depends on the chosen precision. The calculators convert notation; they cannot fix a source measurement that was labeled imprecisely.