Fraction Calculator
Add, subtract, multiply or divide two fractions, including mixed numbers. The result comes back simplified, in both fraction and decimal form, with every step of the working shown so you can follow what happened and why.
Explain like I'm 5 (what even is this calculator?)
Type two fractions, pick plus, minus, times or divide, and you get the answer. If your fraction is one of those "one and a half" mixed numbers, use the whole-number box on the left. The page does the lining-up of denominators, the cancelling down, and the conversion to a decimal. You see all of that working, not just the answer.
Calculate
Enter two fractions and press Calculate.
Prove it
Method: convert any mixed numbers to improper fractions, perform the operation, simplify with the Euclidean gcd, then convert back to a mixed number for display. Decimal is the simplified numerator divided by the denominator.
Useful? Save this calculator: press Ctrl + D to bookmark it.
When to reach for a fraction calculator
Most everyday maths is done in decimals because phones and tills handle decimals natively. Fractions are still the right tool when the numbers come from a recipe, a tape measure, a music score, a chemistry mole ratio, or a school worksheet. Doubling a recipe that calls for 3/4 of a cup of flour is more honest done as 3/4 + 3/4 = 6/4 = 1 1/2 cups than as 0.75 + 0.75 = 1.5 and then back to "a cup and a half". The fraction route preserves the precision the original recipe intended; the decimal route loses it the moment you hit a third or a seventh.
The other reason to keep fractions as fractions is that some of them have no exact decimal. 1/3 is 0.333... forever, 1/7 is 0.142857142857... forever. Round those off and you introduce a small error that compounds across a longer calculation. The simplified fraction stays exact. That is why this calculator gives you both forms: pick whichever the next step in your work needs.
The four operations, in plain terms
Add and subtract need a common denominator. The trick is to multiply each fraction so the bottoms match, then add or subtract the tops. 1/2 plus 1/3 needs sixths: 3/6 plus 2/6 is 5/6. The calculator shows that lining-up step in the Prove it panel because it is where most mistakes happen on paper.
Multiply is the friendly one: top times top, bottom times bottom, and simplify. 2/3 times 3/4 is 6/12, which reduces to 1/2.
Divide is multiplication's mirror: flip the second fraction, then multiply. 1/2 divided by 1/4 is 1/2 times 4/1, which is 4/2, which is 2. Dividing by a fraction smaller than 1 makes the result bigger, which feels wrong until you remember that "how many quarters fit in a half" is genuinely 2.
Common mistakes the calculator helps you avoid
Adding tops and bottoms together. 1/2 plus 1/3 is not 2/5. The bottoms describe the size of the slice, not a quantity to add. Always find the common denominator first.
Forgetting to convert mixed numbers. 1 1/2 plus 2 1/3 is not "1 plus 2, then 1/2 plus 1/3". Convert each to improper form first: 1 1/2 is 3/2, 2 1/3 is 7/3. Then add: 9/6 plus 14/6 is 23/6, which is 3 5/6.
Forgetting to simplify. 6/8 is correct but ugly. The convention in school maths and in most professional settings is to give the answer in simplest form, which is 3/4. The Prove it panel always shows what was cancelled and why.
Sign confusion in mixed numbers. The minus sign on a mixed number applies to the whole quantity, not just the whole-number part. So -1 1/2 means -(1 + 1/2), which is -3/2, not -1 + 1/2. The calculator handles this by treating the whole part as the carrier of the sign.
Edge cases worth knowing
If you enter a denominator of 0, the calculator stops and tells you why. 1/0 is undefined, not infinity, not zero. Same goes for dividing by a fraction that is itself zero: a/b divided by 0/c is refused with a clear message rather than silently returning a misleading number.
If your result simplifies to a whole number (denominator 1), the page shows it as that whole number. 6/4 plus 2/4 is 8/4, which the calculator displays as 2, not "2/1".
If your result is already in simplest form, the gcd shown in the Prove it panel will be 1, which means no simplification step was needed. That is not a bug; it is the calculator being honest about what it did.
Related calculators
Fractions are one form. These cover the same numbers in other shapes.
Frequently asked questions
How do I add fractions with different denominators?
Multiply each fraction so they share a common denominator, add the numerators, then simplify. For 1/2 + 1/3, the common denominator is 6: 1/2 becomes 3/6, 1/3 becomes 2/6, and the sum is 5/6. The calculator above shows this step explicitly in the Prove it panel.
What is a mixed number, and how do I enter one?
A mixed number is a whole number with a fraction next to it, like 1 1/2 (one and a half). Use the whole-number box on the left of each fraction. Leave it at 0 for a plain fraction. The calculator converts mixed numbers into improper fractions before doing the maths, and converts the result back into mixed form for display.
Why does the result not match my calculator's decimal?
Fractions like 1/3 do not have a finite decimal: 1/3 is 0.3333... forever. The decimal shown here is rounded to a sensible number of places, while the fraction form is exact. If precision matters, use the fraction or mixed-number output rather than the decimal.
How does the calculator simplify the result?
It finds the greatest common divisor (gcd) of the numerator and denominator using the Euclidean algorithm, then divides both by it. So 6/8 reduces to 3/4 because gcd(6, 8) is 2. The Prove it panel shows the gcd value used for each calculation.
Does this calculator send my numbers anywhere?
No. Everything runs in your browser. The numbers you type never leave your device.