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Which way round: a decimal onto a mark, or a mark into a decimal.
Decimal to fraction is for a figure that came off a drawing, a spreadsheet or a product sheet and has to be found on a tape. Fraction to decimal is the reverse, for a reading taken off a tape that has to go into a spreadsheet, a cut list or a machine that takes decimals.
The figure in inches, with its decimal part, as the drawing or sheet gives it.
Type it as printed, 5.83 or 0.8125; a fraction typed here, 5 13/16 or 5 13/16", is read as its decimal. A figure in feet goes in as inches: multiply the feet by twelve first, so 2.5 ft is 30, or type it with the foot mark, 2.5', and it is turned into inches for you. A metric figure belongs on the millimetres to inch fraction page, which lands it on a mark without the extra step.
The finest division on the rule you are marking with; the answer rows show all four anyway.
This sets the headline. Everyday tapes carry sixteenths, steel rules and some tapes thirty-seconds over their first foot, and machinist rules sixty-fourths. The four rows under the answer give the nearest mark at each division, so the headline only decides which one is printed largest.
Inches, as a decimal and as a tape mark
5.8125 in (5 13/16 in)
The headline is the nearest mark at the division chosen, as its decimal in full with the mark beside it; a figure exactly halfway between two marks goes to the larger. Each row gives the nearest mark at another division the same way. The difference row says how far the mark sits from the figure entered and which way: positive means the mark is longer than the figure.
- Nearest 1/8 in
- 5.875 in (5 7/8 in)
- Nearest 1/16 in
- 5.8125 in (5 13/16 in)
- Nearest 1/32 in
- 5.84375 in (5 27/32 in)
- Nearest 1/64 in
- 5.828125 in (5 53/64 in)
- Chosen mark minus the figure entered, in millimetres
- -0.4445 mm
- Figure entered, in millimetres
- 148.082 mm
They open the calculator with your figures already in it
Decimal Inches to Fraction Calculator (and Fraction to Decimal): 5.81 in (5 13/16 in) — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- NIST Handbook 44 (2026 edition), Section 5.52 Linear Measures, S.1: a linear measure may be subdivided in inches and binary submultiples of the inch — the halves, quarters, eighths, sixteenths, thirty-seconds and sixty-fourths offered here
- NIST Handbook 44 (2026 edition), Appendix C, General Tables of Units of Measurement: 1 inch = 2.54 centimetres exactly and 12 inches = 1 foot, per the Federal Register of 1 July 1959 (24 FR 5348)
Inputs used
- Convert
- Decimal to tape mark
- Decimal Inches (in)
- 5.83
- Round to the Nearest
- 1/16 in
- Whole Inches (in)
- 5
- Fraction: Top Number
- 13
- Fraction: Bottom Number
- 16 (sixteenths)
Intermediate steps
- Nearest 1/8 in
- 5.875 in (5 7/8 in)
- Nearest 1/16 in
- 5.8125 in (5 13/16 in)
- Nearest 1/32 in
- 5.84375 in (5 27/32 in)
- Nearest 1/64 in
- 5.828125 in (5 53/64 in)
- Chosen mark minus the figure entered, in millimetres
- -0.4445 mm
- Figure entered, in millimetres
- 148.082 mm
Confidence note: The headline is the nearest mark at the division chosen, as its decimal in full with the mark beside it; a figure exactly halfway between two marks goes to the larger. Each row gives the nearest mark at another division the same way. The difference row says how far the mark sits from the figure entered and which way: positive means the mark is longer than the figure.
What this calculation does not cover
- The nearest mark is nearest in either direction, so the rounded reading can sit up to half a division long or short: 1/32 in (0.8 mm) when rounding to sixteenths and 1/128 in (0.2 mm) when rounding to sixty-fourths. Where only one direction is safe, a hole that must clear or a tenon that must fit, round toward that side instead of to the nearest mark.
- A decimal printed to three places promises a thousandth of an inch, and no tape or rule can be read that finely. When the figure comes from a machining drawing with a tight tolerance, the part is measured with calipers or a micrometer, not marked from a fraction.
- Only the fractions a rule carries are offered: halves, quarters, eighths, sixteenths, thirty-seconds and sixty-fourths, the binary divisions of the inch. A third or a fifth of an inch has no mark, so it is rounded to the nearest one that does.
- Lengths stay in inches throughout, so 37 13/16 in is not split into 3 ft 1 13/16 in. For a reading over a foot in feet and inches, the feet and inches calculator rounds the same way with the feet taken out.
Add the equipment this sizes
This result is a specification — 5.8125 in (5 13/16 in) — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-10-05 · v1.0.0
Regulatory standards & verification citations2
- NIST Handbook 44 (2026 edition), Section 5.52 Linear Measures, S.1: a linear measure may be subdivided in inches and binary submultiples of the inch — the halves, quarters, eighths, sixteenths, thirty-seconds and sixty-fourths offered here
- NIST Handbook 44 (2026 edition), Appendix C, General Tables of Units of Measurement: 1 inch = 2.54 centimetres exactly and 12 inches = 1 foot, per the Federal Register of 1 July 1959 (24 FR 5348)
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