Fraction Calculator
Add, subtract, multiply or divide two fractions and get the simplified result and its decimal value.
How fractions are combined
For addition and subtraction the fractions are put over a common denominator; for multiplication the numerators and denominators are multiplied; division multiplies by the reciprocal. The answer is then reduced by dividing by the greatest common divisor.
FAQ
How is the result simplified?
By dividing the numerator and denominator by their greatest common divisor (GCD).
Denominators cannot be zero.
Use the result with confidence
Enter whole-number parts
Enter the numerator above the denominator for each fraction, then choose the operation. Negative numerators or denominators are supported. Decimal input is rejected rather than silently rounded. To enter 0.5, use 1/2; a denominator of zero is never valid.
Why 1/2 + 1/3 becomes 5/6
The shared denominator is 6: 1/2 becomes 3/6 and 1/3 becomes 2/6. Adding the numerators gives 5/6, approximately 0.833333. Multiplication uses numerator × numerator and denominator × denominator; division multiplies by the second fraction’s reciprocal.
Read the exact result first
The fraction is reduced using the greatest common divisor, with its sign on the numerator. The decimal is an approximation. Integer arithmetic preserves large whole numbers (up to 120 digits per input). Dividing by 0/3 is invalid even though its denominator is nonzero.
The example changes this calculator’s fields. It does not save or replace a journal or backup.