How to use this calculator
Enter two fractions using the whole number, numerator, and denominator fields. The whole number is optional, leave it blank or set it to 0 for simple fractions. Choose your operation (add, subtract, multiply, or divide) and the calculator instantly shows the result as a simplified fraction, mixed number, and decimal.
Every calculation includes a step-by-step breakdown so you can follow the math. Use the "Simplify a Fraction" tool below the main calculator to quickly reduce any fraction to its lowest terms.
How to add fractions step by step
Adding fractions requires a common denominator. First, find the least common denominator (LCD) of both fractions. Then multiply each fraction's numerator by whatever factor makes its denominator equal to the LCD. Add the adjusted numerators and place the sum over the common denominator. Finally, simplify the result by dividing both numerator and denominator by their greatest common divisor.
For example: 2/3 + 1/4. The LCD of 3 and 4 is 12. Convert: 8/12 + 3/12 = 11/12. Since 11 and 12 share no common factors, 11/12 is already simplified.
Common fraction-decimal equivalents
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/8 | 0.125 | 12.5% |
| 1/6 | 0.1667 | 16.67% |
| 1/4 | 0.25 | 25% |
| 1/3 | 0.3333 | 33.33% |
| 3/8 | 0.375 | 37.5% |
| 1/2 | 0.5 | 50% |
| 5/8 | 0.625 | 62.5% |
| 2/3 | 0.6667 | 66.67% |
| 3/4 | 0.75 | 75% |
| 7/8 | 0.875 | 87.5% |
Frequently asked questions
How do you add fractions with different denominators?
Find the least common denominator (LCD), convert each fraction so they share that denominator, add the numerators, and simplify. For example, 1/3 + 1/4: LCD is 12, so 4/12 + 3/12 = 7/12.
How do you multiply fractions?
Multiply the numerators together and the denominators together, then simplify. For example, 2/3 × 3/4 = 6/12 = 1/2. You don't need a common denominator for multiplication.
How do you simplify a fraction?
Find the greatest common divisor (GCD) of the numerator and denominator, then divide both by it. A fraction is fully simplified when the only common factor is 1.
How do you divide fractions?
Flip the second fraction (take its reciprocal) and multiply. For example, 3/4 ÷ 2/5 becomes 3/4 × 5/2 = 15/8, which is 1 7/8 as a mixed number.