How it’s calculated
A fraction is a division: divide the numerator by the denominator to get the decimal. To go the other way, write the decimal over a power of ten and simplify by the greatest common divisor (GCD).
A fraction in lowest terms gives a terminating decimal only if its denominator has no prime factors other than 2 and 5; otherwise the digits repeat (1/3 = 0.333…). For repeating decimals, type enough digits and the converter finds the simplest fraction that matches, e.g. 0.333333333333 → 1/3.
Frequently asked questions
How do I convert a decimal to an inch fraction?
Multiply by 16 (or 32, 64), round to a whole number and put it over 16, then simplify. 0.3 in × 16 = 4.8 → 5/16 in. Pick the ruler resolution in the "round to nearest" box.
What is 1/3 as a decimal?
0.333… with the 3 repeating forever. It cannot be written exactly as a finite decimal.
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Sources
- Prealgebra 2e, §5.3 Decimals and Fractions — OpenStax
- Prealgebra 2e, §5.1 Decimals — OpenStax
Formulas are taken from the free public references above. Results are provided “as is” for informational and educational purposes only. See our disclaimer.
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