Fraction calculator

Enter a decimal, fraction, or mixed number.

• Decimals parse as exact rationals (fraction.js): 0.1 is 1/10 exactly, no floating-point rounding anywhere in the pipeline.
• Fractions reduce to lowest terms with the sign on the numerator; the gcd row shows what the reduction divided out of your typed digits.
• Improper fractions also read as mixed numbers ("4/3" and "1 1/3" are the same number, both shown).
• Decimal expansions are exact, with repeating digits in parentheses. 0.(3) is 1/3 forever, not "0.3333333333".
• Scientific notation (1e-3) is refused, with the plain form suggested: a refusal beats a silent re-reading.