Fraction Calculator — Add, Subtract, Multiply & Divide
This free fraction calculator handles all four arithmetic operations on fractions and returns the answer in three forms simultaneously: the simplified fraction in lowest terms, the mixed number (when applicable), and the decimal equivalent. It also shows the step-by-step working so you can follow the method and learn from each calculation.
Enter numerator A, denominator B, choose an operation, enter numerator C and denominator D, then click Calculate. The answer appears instantly — no reloads, no sign-up.
Fraction Operation Rules
Cross-multiply the numerators, add them, place over the product of both denominators. Then simplify by dividing by the GCD.
Same as addition but subtract the cross-multiplied numerators. Result can be negative if A/B < C/D.
Multiply numerators together and denominators together. Then simplify. The simplest of all four operations — no common denominator needed.
"Keep, Change, Flip" — keep the first fraction, change ÷ to ×, flip (reciprocal) the second fraction. Then multiply and simplify.
How Fractions Are Simplified
Every result is reduced to its lowest terms using the Greatest Common Divisor (GCD). The GCD is found using the Euclidean algorithm:
gcd(a, 0) = a
Example: gcd(12, 8)
→ gcd(8, 4) → gcd(4, 0) = 4
12/8 ÷ 4/4 = 3/2
Once simplified, if the numerator is larger than the denominator (an improper fraction), the result is also expressed as a mixed number. For example, 3/2 becomes 1½.
Worked Example: 2/3 + 3/4
Frequently Asked Questions
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