Fraction Calculator
Free, with no sign up. Calculations run on your device; your entries stay in this browser.
Fractions here are unitless numbers. Enter integers, fractions such as 3/4, or mixed numbers such as -1 1/2. A leading minus applies to the whole mixed number. Arithmetic uses exact BigInt integers; only the decimal display may be approximate.
Your result
a/b ± c/d = (ad ± bc)/bd; (a/b) × (c/d) = ac/bd; (a/b) ÷ (c/d) = ad/bc. Divide numerator and denominator by their greatest common divisor.
Primary source: California Department of Education mathematics standards (rational-number arithmetic).
Worked example
1 1/2 + 2/3 = 3/2 + 2/3 = 13/6 = 2 1/6 ≈ 2.1666666666666666.
Convert a terminating or repeating decimal with Decimal to Fraction.
How to use this tool
Enter your values, choose the options, and select Calculate to see the result and formula.
Frequently asked questions
Can I calculate with negative mixed numbers?
Yes. -1 1/2 means -(1 + 1/2), which equals -3/2.
Are large fractions exact?
Yes. Numerators and denominators use BigInt arithmetic, with a 300-character limit per input. The decimal display shows at most 16 fractional digits.
What happens when I divide by zero?
Zero denominators and division by a zero-valued fraction produce an error.