Fraction Calculator: Add, Subtract, Multiply and Divide Fractions
Our fraction calculator adds, subtracts, multiplies and divides fractions and shows every step. It also works as a mixed numbers calculator, so you can type 2 1/3 and get a clean answer. Results come as a simplified fraction, a mixed number, a decimal and a percent.
What Is a Fraction Calculator?
A fraction calculator does arithmetic on numbers written as one number over another. It handles the four basic operations, converts between forms and reduces the answer to lowest terms. You get the result plus the steps behind it.
Fractions show up in recipes, measurements, school math and woodworking. Doing them by hand means finding common denominators, flipping numbers and hunting for common factors. A fractions calculator removes the busywork so you can check your own method.
How to Use the Fraction Calculator
- Pick a task: add, subtract, multiply or divide two numbers, or simplify one fraction.
- Type the first number. Use the Whole box only for a mixed number such as 2 1/3.
- Choose the operation and type the second number.
- Read the answer and the steps in the result panel.
The result panel of this mixed numbers calculator shows the answer as a fraction, a mixed number, a decimal and a percent. The steps list explains the common denominator, the flip or the simplification. The online fraction calculator also warns you when a bottom number is zero.
How to Add and Subtract Fractions
Fractions can only be added or subtracted when they share a denominator. Find the least common denominator, which is the smallest number both bottoms divide into. Rewrite each fraction over it, then add or subtract the top numbers and keep the bottom.
For 1/2 + 1/3 the least common denominator is 6. The fractions become 3/6 and 2/6, and the sum is 5/6. If the denominators already match, skip the rewrite and combine the top numbers directly. Mixed numbers work the same way, and a mixed numbers calculator turns them into improper fractions first.
How to Multiply Fractions
Multiplication is easier than addition because no common denominator is needed. Multiply the top numbers together and multiply the bottom numbers together. Then reduce the answer.
For 2/3 × 3/4 the tops give 6 and the bottoms give 12, so the product is 6/12. The greatest common divisor is 6, which reduces it to 1/2. The fraction calculator shows this reduction as its last step. For mixed numbers, convert first, as a mixed numbers calculator does.
How to Divide Fractions
Dividing by a fraction means multiplying by its flip. The flip, also called the reciprocal, swaps the top and the bottom. So 3/5 ÷ 2/3 becomes 3/5 × 3/2, which equals 9/10.
You cannot divide by zero, and the number 0/5 counts as zero. The tool stops with a message in that case. Dividing a fraction by a whole number works the same way, because 4 is just 4/1.
Mixed Numbers Calculator
A mixed number combines a whole number and a fraction, like 4 5/12. To calculate with one, first turn it into an improper fraction. Multiply the whole part by the bottom, add the top and keep the same bottom.
The mixed numbers calculator does this conversion for you and shows it as the first step. For 1 3/4 the result is 7/4, because 1 × 4 + 3 = 7. At the end it turns the answer back into a mixed number when the top is larger than the bottom.
| Mixed number | Improper fraction |
| 1 1/2 | 3/2 |
| 2 1/3 | 7/3 |
| 3 3/4 | 15/4 |
| 4 5/12 | 53/12 |
Negative mixed numbers take their sign from the whole part, so −1 1/2 means minus one and a half. Type the minus sign in the Whole box and the tool treats the whole number as negative. A negative top number is only for plain fractions such as −3/4.
Simplifying Fractions
A fraction is in lowest terms when the top and bottom share no factor except 1. To simplify, divide both by their greatest common divisor. Euclid's method finds that divisor with repeated division.
Take 18/24, where the method gives 24 = 1 × 18 + 6 and then 18 = 3 × 6 + 0, so the greatest common divisor is 6. Dividing both numbers by 6 gives 3/4. The simplify task in the fraction calculator prints each of these lines. You can also use the GCD and LCM calculator to check a divisor.
Fraction Calculator Examples
Adding Mixed Numbers
Add 1 3/4 and 2 2/3. As improper fractions these are 7/4 and 8/3, with a least common denominator of 12, so they become 21/12 and 32/12. The sum is 53/12, which the mixed numbers calculator shows as 4 5/12 or 4.416667.
Multiplying Mixed Numbers
Multiply 2 1/3 by 1 1/2. The improper forms are 7/3 and 3/2, and the product is 21/6. The greatest common divisor is 3, so the answer simplifies to 7/2, or 3 1/2.
Subtracting and Dividing
Subtract 1/6 from 3/4 to get 9/12 − 2/12 = 7/12. Divide 3/5 by 2/3 and you flip the second fraction to get 9/10, which is 0.9 or 90 percent. Both answers are already in lowest terms.
A Negative Result
Add −1 1/2 and 3/4. In improper form the numbers are −3/2 and 3/4, which become −6/4 and 3/4. The sum is −3/4, or −0.75.
Fraction Rules at a Glance
| Operation | Rule | Example |
| Add | Common denominator, then add the tops | 1/2 + 1/3 = 5/6 |
| Subtract | Common denominator, then subtract the tops | 3/4 − 1/6 = 7/12 |
| Multiply | Tops times tops, bottoms times bottoms | 2/3 × 3/4 = 1/2 |
| Divide | Multiply by the flip | 3/5 ÷ 2/3 = 9/10 |
| Simplify | Divide both by the greatest common divisor | 18/24 = 3/4 |
Always reduce at the end, or earlier if a top and a bottom share a factor. Reducing early keeps the numbers small and cuts the chance of an error. Our tool does it for you in the last step.
Fractions in Daily Life
Cooking is the most common place people meet fractions. A recipe that calls for 3/4 cup of flour needs 1 1/2 cups when you double it. Carpenters add mixed numbers like 5 3/8 inches and 2 1/4 inches all day. A fractions calculator saves time on both jobs and avoids a costly mistake.
Medicine, sewing and knitting also use fractional amounts. In each case the arithmetic is the same as in school. A mixed numbers calculator handles the whole part and the fraction part together.
Comparing Two Fractions
To see which of two fractions is larger, subtract one from the other. A positive answer means the first fraction is larger, and a negative answer means the second one is. Zero means they are equal. For example, 5/8 − 2/3 gives −1/24, so 2/3 is the larger one.
You can also compare decimals. Divide each top by its bottom and read the decimal line in the result panel. The tool prints up to 6 decimal places and marks repeating digits.
Tips for Using a Mixed Numbers Calculator
Estimate the answer before you press anything, so you can spot a typo. Check that the answer has the right size, since adding two numbers above 1 should give a result above 2. An online fraction calculator is a checker and not a replacement for practice. Do the problem on paper first, then compare each step with the tool.
Common Fraction Mistakes
- Adding the tops and the bottoms, as in 1/2 + 1/3 = 2/5. The correct answer is 5/6.
- Forgetting to flip the second fraction when dividing.
- Leaving an answer unreduced, such as 6/12 instead of 1/2.
- Mixing up a mixed number like 2 1/3 with the product 2 × 1/3.
- Ignoring signs when a number is negative.
Each of these mistakes is easy to catch with a step display. Compare your own work against each line of the tool. A mixed numbers calculator that shows its steps makes the error visible.
Why Use Our Fraction Calculator
It handles whole numbers, plain fractions and mixed numbers in the same boxes. Every answer comes with steps, a decimal with repeating digits marked and a percent. Type your fractions and solve them now.
Frequently asked questions
Is this fraction calculator free?
Yes, it is free and runs in your browser.
How do I enter a mixed number?
Type the whole part in Whole, then the top and bottom of the fraction.
How does the mixed numbers calculator show a negative value?
Put the minus sign in the Whole box, or in Top for a plain fraction.
Can I use it to simplify a fraction?
Yes, choose the simplify task and type one fraction.
Can the mixed numbers calculator divide mixed numbers?
Yes, it converts them to improper fractions and flips the second one.
Does it reduce answers automatically?
Yes, every answer is shown in lowest terms.
Can it handle whole numbers?
Yes, leave Top and Bottom empty and type only the Whole box.
What happens when the bottom number is zero?
The tool shows a message, because a fraction cannot have a zero bottom.
How large can the numbers be?
Each box takes up to 15 digits, and the math is exact.
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