Fraction Calculator (Add, Subtract, Multiply, Divide, Reduce)
Two fractions a/b and c/d can be added, subtracted, multiplied, or divided with integer arithmetic, then reduced by their greatest common divisor. This page rounds inputs to integers, performs the operation, and prints the reduced improper fraction, a mixed number when useful, and the decimal value. Division by zero is rejected.
Reduced fraction5/6
Mixed / whole form5/6
Decimal0.833333
Numerator5
Denominator6
How this calculation works
Add: (n1/d1) + (n2/d2) = (n1×d2 + n2×d1) / (d1×d2). Subtract uses a minus in the numerator.
Multiply: (n1×n2)/(d1×d2). Divide: (n1×d2)/(d1×n2) — invert the second fraction and multiply.
Reduce by dividing numerator and denominator by gcd(|n|,|d|). Negative signs are moved onto the numerator.
Inputs are rounded to integers so 1.0/2.0 is 1/2. For repeating decimals that are not exact fractions, convert yourself first.
Worked example
1/2 + 1/3 = 5/6. 3/4 − 1/2 = 1/4. 2/3 × 3/5 = 2/5. (1/2) ÷ (1/4) = 2. 3/4 + 5/4 = 2.
Frequently asked questions
How do I enter a whole number?
Use denominator 1 (3/1). Mixed 1 1/2 is 3/2 — type 3 and 2.
Why did I get an integer?
The reduced denominator is 1, so the result is a whole number (for example (1/2)÷(1/4)=2).
Can denominators be negative?
The reducer flips a negative denominator onto the numerator so the printed fraction has a positive bottom.
Lowest terms always?
Yes, via Euclidean gcd. 2/4 becomes 1/2.
Complex fractions or variables?
Not supported. Numeric integer fractions only.
Are inputs stored?
No. Browser only.
This tool is provided for general information only. Verify important figures independently. · Last reviewed: August 25, 2026