Fraction Calculator
Add, subtract, multiply, or divide fractions and mixed numbers — or simplify a single fraction to its lowest terms. Exact integer math, no rounding errors.
Calculated locally. Exact integer math — never rounded.
Common questions
What operations does this support?
Addition, subtraction, multiplication, and division of two fractions or mixed numbers, plus a separate mode to simplify a single fraction to its lowest terms. Every result is also shown as a mixed number and a decimal for reference.
Does this support mixed numbers (like 1 1/2)?
Yes — enter a whole number alongside the numerator and denominator for either number. Leave the whole number blank (or 0) for a plain fraction, or leave the numerator and denominator as 0/1 for a plain whole number.
Why is the math exact instead of using decimals?
Fractions are calculated using whole-number numerators and denominators the entire way through (cross-multiplication and GCD-based simplification), never converted to a decimal until the final display. This avoids the rounding errors that floating-point decimal math can introduce, so results like 1/3 + 1/3 come out as exactly 2/3, not a repeating decimal approximation.
What happens if I divide by zero or enter 0 as a denominator?
A denominator of 0 isn't a valid fraction, and dividing by a fraction whose value is 0 is undefined — both show a clear error instead of a result.