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Repeating Decimal to Fraction Calculator

Convert recurring decimals to exact reduced fractions. Enter a repetend such as 0.1(6), see the 10^k algebra, simplify by GCD, and check the answer by expanding the fraction back to a decimal.

All calculation runs in your browser with integer arithmetic. Inputs are not sent to a server.

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Input

Use parentheses for the repeating digits, such as 0.1(6) or 0.(142857). With an ellipsis such as 0.333..., a pattern must appear at least twice; check the interpretation shown in the result. Enter up to 80 digits in total, including the integer part and leading zeros. The repeating block can contain up to 60 digits.

Use k only in Last k mode. Example: type 0.1666 and k = 1 to mean 0.1666....

Terminating decimal mode accepts ordinary decimals, such as 0.333 for 333/1000. Parentheses and an ellipsis are not accepted in this mode.

Result

Exact fraction-
Mixed number-
Raw fraction-
GCD-

Bar notation

Reverse check

The reduced fraction expands back to .

10^k algebra steps

    GCD simplification

      The result uses exact BigInt integer arithmetic. No floating-point rounding is used to build the fraction.

      When to use this page

      Use this page when you already know which digits repeat and want the exact fraction. For fraction arithmetic, use the fraction calculator. To reduce an existing fraction, use the fraction simplifier. To see long division steps that create a repeating decimal, use the long division calculator.

      FAQ

      How do I type the repeating part?

      Use parentheses for the repetend, such as 0.1(6) or 0.(142857). You can also choose Last k digits repeat, type a normal decimal such as 0.1666, and set k to 1.

      Why does 0.999... become 1?

      The algebra gives 9x = 9 for x = 0.(9), so x = 1. The calculator shows this as a normal exact simplification, not as rounding.

      What is the difference between a terminating decimal and a repeating decimal?

      A terminating decimal has no repeating block and uses a place-value denominator such as 10, 100, or 1000. A repeating decimal subtracts two powers of 10 so the repeating tail cancels.

      Are the fractions exact?

      The fraction is exact for the repeating block you specify or the calculator interprets. Integer arithmetic avoids rounding when constructing and reducing the fraction. For ellipsis input, check the displayed interpretation first.

      Can every decimal ending in an ellipsis be converted to an exact fraction?

      No. An ellipsis does not specify all the digits that follow. Use parentheses to state the repeating block explicitly. When a pattern appears at least twice, this calculator can infer a block and shows how it interpreted the input. Check that interpretation before using the result.

      Can I use bar notation instead of parentheses?

      Type the repeated digits in parentheses, then read the result in bar notation. For example, enter 0.1(6) for 0.16 with only the 6 repeating.