Fraction Calculator
Add, subtract, multiply or divide two fractions or mixed numbers. The calculator shows the simplified fraction, the mixed number, the decimal and the key step, such as the common denominator or the reciprocal.
Fraction calculator
How to use the fraction calculator – add, subtract, multiply and divide fractions
- Enter the first fraction. Type the numerator and denominator, and a whole number if it is a mixed number.
- Choose the operation. Pick add, subtract, multiply or divide.
- Enter the second fraction. Type it the same way.
- Read the result. The answer is shown in lowest terms, as a mixed number if it is above 1, with the decimal and the working step.
Rules for each operation
a/b + c/d = (ad + bc) ÷ bd
a/b − c/d = (ad − bc) ÷ bd
a/b × c/d = ac ÷ bd
a/b ÷ c/d = ad ÷ bc
The calculator uses the lowest common denominator rather than bd, which keeps the numbers small, and then simplifies by the greatest common divisor.
Worked examples
1/2 + 1/3. The common denominator is 6. 3/6 + 2/6 = 5/6, or 0.8(3) as a decimal.
3/4 − 1/6. The common denominator is 12. 9/12 − 2/12 = 7/12.
2 1/2 × 1 2/3. Convert to improper fractions: 5/2 × 5/3 = 25/6, which is 4 1/6.
3/4 ÷ 2/5. 3/4 × 5/2 = 15/8, or 1 7/8.
1 1/2 + 2 3/4. 3/2 + 11/4 = 6/4 + 11/4 = 17/4, or 4 1/4.
Mixed numbers
A mixed number is a whole number plus a fraction. To calculate with one, convert it to an improper fraction by multiplying the whole number by the denominator and adding the numerator: 2 1/2 = (2 × 2 + 1)/2 = 5/2. Do the sum, then convert back by dividing the numerator by the denominator and keeping the remainder as the new numerator.
Common mistakes
Adding the denominators is the classic error: 1/2 + 1/3 is not 2/5. Another is forgetting to flip the second fraction when dividing. When subtracting a larger fraction from a smaller one the answer is negative, as in 1/4 − 3/4 = −1/2. Finally, simplify at the end, or the answer may look different from the one in the textbook although it is the same value.
Related tools
To see any answer as a decimal, use the fraction to decimal calculator. For ruler-style fractions, the decimal to fraction calculator finds the nearest 1/16 or 1/32. When fractions describe a comparison of quantities, the ratio calculator simplifies and scales them.
Frequently asked questions
How do you add fractions with different denominators?
Find a common denominator, convert both fractions, add the numerators and simplify. 1/2 + 1/3 = 3/6 + 2/6 = 5/6.
How do you subtract fractions?
Use a common denominator and subtract the numerators. 3/4 − 1/6 = 9/12 − 2/12 = 7/12.
How do you multiply fractions?
Multiply the numerators together and the denominators together, then simplify. 2/3 × 3/4 = 6/12 = 1/2.
How do you divide fractions?
Multiply by the reciprocal of the second fraction. 3/4 ÷ 2/5 = 3/4 × 5/2 = 15/8 = 1 7/8.
How do I enter a mixed number?
Type the whole number, then the numerator and denominator. 2 1/2 is whole 2, numerator 1 and denominator 2. For a negative mixed number, put the minus sign on the whole number.
What does simplifying a fraction mean?
Dividing the numerator and denominator by their greatest common divisor, so 6/8 becomes 3/4. A fraction is in lowest terms when the only common factor is 1.
What is an improper fraction?
A fraction whose numerator is larger than its denominator, such as 25/6. It equals the mixed number 4 1/6.
Related calculators
Fraction to Decimal Calculator – With Repeating Decimals
Fraction or mixed number to decimal and percent, with repeating decimals.
Decimal to Fraction Calculator – Exact and Closest Fractions
Decimal to exact fraction, mixed number and nearest 1/16, 1/32 or 1/64.
Ratio Calculator – Simplify, Solve and Split by Ratio
Simplify ratios, solve proportions and split a total by a ratio.
Percentage Calculator – What Is X% of Y?
X% of Y, X is what % of Y, and X is Y% of what number.
Sources and references
About this calculator
Written and maintained by Rashid Mehmood, founder of CalcTen. The formulas are unit-tested against hand-worked examples, and the content is reviewed whenever product sizes or guidance change. Last updated 14 November 2026. See our editorial policy.
Results are calculated from the numbers you enter and shown with the working. Rounding is applied only when displaying results. Grade and GPA scales, and weighting rules, vary by school, so confirm with your institution. Read the disclaimer.