Inches To Fraction Calculator
An inches to fraction calculator converts decimal inch measurements into the fractions marked on a tape measure and ruler. Enter a decimal value, pick the precision your trade uses (1/16 for carpentry, 1/32 for fine woodwork, 1/64 for machining), and get the nearest fraction plus feet-and-inches, metric equivalents, and the rounding error. New in this version: enter the measurement in millimeters, centimeters, meters, or feet, and convert a whole cut list at once with the batch converter.
The fraction is the nearest mark you can actually set on a tape at the chosen precision; the exact decimal and rounding error are shown so nothing is hidden.
How the conversion works
The tool splits your decimal into whole inches and a leftover decimal, multiplies the leftover by the chosen denominator (16 for sixteenths, 32 for thirty-seconds), and rounds to the nearest whole numerator. It then simplifies the fraction with the greatest common divisor, so 12/16 becomes 3/4, and it handles the edge case where rounding rolls up to a whole inch: 1.99999 at 1/16 precision correctly returns 2″, not the broken “1 1/1″” that naive converters produce. For a pure math conversion without the tape-measure framing, see our decimal to fraction calculator.
Choosing the right precision for your trade
Most US tape measures are graduated to 1/16 inch, which makes 1/16 the right default for general carpentry, framing, and DIY. Fine woodworking and cabinetry usually call for 1/32. Machining and precision metalwork need 1/64. Coarser settings (1/2, 1/4, 1/8) suit rough carpentry and quick estimates. A finer denominator always shrinks the rounding error, but the fraction gets harder to find on the tape, so pick the coarsest resolution that keeps the error inside your job’s tolerance. The tool shows the rounding error on every conversion so you can judge.
Reading a tape measure
A standard tape has four tiers of marks between whole-inch numbers. The longest marks are the half inches, the next tier the quarters, then the eighths, and the shortest the sixteenths. Count forward from the last whole inch and add the fraction: two marks past 2″ on a sixteenth tape is 2 2/16, which simplifies to 2 1/8″. Converting the decimal first and then hunting for the nearest fraction mark is the fastest way to transfer a caliper or laser reading onto a rule.
Common decimal to fraction equivalents
Memorize the eighths and the rest follows: 0.125 = 1/8, 0.25 = 1/4, 0.375 = 3/8, 0.5 = 1/2, 0.625 = 5/8, 0.75 = 3/4, 0.875 = 7/8. Common sixteenths: 0.0625 = 1/16, 0.1875 = 3/16, 0.3125 = 5/16, 0.4375 = 7/16, 0.5625 = 9/16, 0.6875 = 11/16, 0.8125 = 13/16, 0.9375 = 15/16. Anything that falls between these marks gets rounded to the nearest one at your chosen precision, with the error displayed.
Worked example, verified against the tool
Convert 14.72″ at 1/16 precision. Decimal part 0.72 × 16 = 11.52, rounds to 12; 12/16 simplifies to 3/4, giving 14 3/4″. That fraction equals exactly 14.75″, so the rounding error is 0.03″ (the fraction is 0.03″ larger than the input). Feet and inches: 1′ 2 3/4″. Metric: 373.89 mm (37.39 cm). Every figure matches the tool’s output exactly.
Convert from metric or feet, and convert whole lists
Drawings do not always arrive in inches. The input-unit selector converts millimeters, centimeters, meters, or feet to decimal inches first, then runs the same fraction math: 50 mm becomes 1.9685 inches, which at 1/16 precision is 1 15/16 inches, exactly as the worked examples on the mm-to-fraction pages show. Below the main result, the list converter takes a whole cut list at once: paste measurements one per line or comma-separated and get every fraction in one table, using the same unit and precision. A 50-value cap keeps the output readable.
What competing calculators miss
The top inches-to-fraction tools each cover part of the job. OnlineMiniTools accepts inches, millimeters, centimeters, meters, and feet, which is the broadest input of the group, but it converts one value at a time. OmniCalculator’s strength is its giant fraction-to-decimal-to-millimeter reference table, and InchCalculator’s is the decimal chart with tape-mark hints, but neither converts a pasted list. SavvyCalculator’s mm-to-fraction page explains the math well for a single value. None of the top results combine multi-unit input with batch list conversion in one tool. This page does both, keeps the rollover fix (1.99999 becomes 2, not a broken fraction), and shows the rounding error instead of hiding it.
Frequently asked questions
How do you convert decimal inches to a fraction?
Multiply the decimal part by a power-of-two denominator (16 for sixteenths), round to the nearest whole number for the numerator, and simplify. For example, 0.72 × 16 = 11.52 rounds to 12, and 12/16 simplifies to 3/4.
What precision should I use for woodworking?
Use 1/16 inch for general carpentry and 1/32 for fine woodworking and cabinetry; both match standard tape measure markings. Machining work needs 1/64.
Why does the tool show a rounding error?
Because most decimals fall between tape marks. The tool picks the nearest markable fraction and shows the exact difference, so you know whether the fraction is slightly larger or smaller than your input and by how much.
Can the tool convert values over 12 inches?
Yes. For inputs of 12 inches or more it also shows the feet-and-inches form, for example 14 3/4″ becomes 1′ 2 3/4″, which is how dimensions are usually spoken on site.
Does it show metric equivalents?
Yes. Every conversion includes millimeters and centimeters (14.72″ = 373.89 mm), which is handy when a drawing mixes imperial fractions with metric dimensions.
What happens with negative measurements?
The tool converts the absolute value and re-applies the negative sign, so −2.5 at 1/16 precision returns −2 1/2″. Negative offsets come up in machining and layout work.
Why did my old converter show something like “1 1/1 inch”?
That is the classic rollover bug: when the decimal part rounds all the way up (for example 1.99999 at 1/16), naive code simplifies 16/16 to 1/1 instead of carrying the whole inch. This tool carries the rollover, so 1.99999 correctly returns 2″.
Can I convert millimeters to fractions of an inch?
Yes. Choose Millimeters in the input-unit selector and enter the value: 50 mm converts to 1.9685 inches, which is 1 15/16 inches at 1/16 precision. The metric equivalents line also shows every result in mm and cm.
Can I convert a whole list of measurements at once?
Yes. Use the list converter below the main result: paste up to 50 measurements, one per line or comma-separated, and it converts each one using the selected unit and precision. Handy for cut lists.