Fraction Calculator
Add, subtract, multiply and divide fractions or mixed numbers and get the answer fully simplified, as a mixed number, a decimal and a percentage. Every calculation comes with the complete working — the common denominator, the arithmetic and the final simplification — so you can follow the method, not just copy the result.
- Full step-by-step working
- Whole and mixed numbers
- Auto-simplified answers
- Decimal and percentage output
Calculate with fractions
Answer in lowest terms
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Enter two fractions and pick an operation to see the answer and the working.
- —Improper fraction
- —Mixed number
- —Decimal
- —Percentage
Step-by-step solution
Step 1 — write both as improper fractions
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Step 2 — use a common denominator
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Step 3 — do the arithmetic
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Step 4 — simplify
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Convert a decimal to a fraction
Enter a terminating decimal such as 0.625 or 2.75 to see it as a fraction in lowest terms.
Why this fraction calculator is better
The answer is the easy part. What people searching for a fraction calculator usually need is to see where their own working went wrong.
Every step shown free
The improper conversion, the common denominator, the arithmetic and the simplification are all laid out. No subscription, no locked working.
Mixed numbers handled properly
Enter two and a half as a whole number and a fraction rather than converting it yourself first, and negatives work in either field.
Four formats at once
Improper fraction, mixed number, decimal and percentage together, because different questions want the answer in different forms.
Lowest terms automatically
The greatest common divisor is found and shown, so you can see exactly what was cancelled rather than wondering how the answer shrank.
Decimal converter included
Turn a terminating decimal back into a fraction in lowest terms without leaving the page or opening a second tool.
Instant and private
Results update as you type, everything runs in your browser, and there is no sign-up, no advert wall and no data collection.
How to add, subtract, multiply and divide fractions
The calculator follows the standard school method. Here it is in four moves.
Turn mixed numbers into improper fractions
Multiply the whole number by the denominator and add the numerator. Two and a half becomes five halves, because two times two plus one is five.
For adding and subtracting, match the denominators
Find the lowest common denominator and rescale both fractions to it. Only then do you add or subtract the numerators; the denominator stays as it is.
For multiplying and dividing, no common denominator is needed
Multiply straight across, top by top and bottom by bottom. To divide, flip the second fraction upside down and multiply instead.
Simplify to lowest terms
Divide the numerator and denominator by their greatest common divisor, then convert back to a mixed number if the question asked for one.
Where fraction arithmetic actually comes up
Well beyond the maths classroom, and usually when getting it wrong is expensive.
- Homework and revision. Check an answer and compare the working line by line to find the exact step where your version diverged.
- Scaling recipes. Two thirds of a cup times one and a half is not something to guess at when baking.
- Woodwork and construction. Imperial measurements live in sixteenths and thirty-seconds of an inch, and cuts are unforgiving.
- Sewing and craft. Seam allowances, pattern scaling and fabric widths are almost always quoted as fractions.
- Teaching and tutoring. Put the deviation-free working on screen so a class can see why denominators must match before adding.
- Converting between systems. Turn a decimal reading from a digital tool into the fraction stamped on a physical ruler or spanner.
Fraction calculator FAQs
The rules that most often get mixed up.
Why do denominators have to match before adding fractions?
Because the denominator says what size the pieces are. A half and a third are different-sized pieces, so counting them together is meaningless until both are expressed in the same size — sixths, in that case. Once both are sixths you simply count the pieces, which is why the numerators add but the denominator does not.
Do I need a common denominator to multiply fractions?
No, and this is the most common confusion. Multiplication and division work straight across: multiply the numerators together and the denominators together. Only addition and subtraction need a common denominator, which is why the second step of the working disappears when you switch to times or divide.
How do I divide by a fraction?
Flip the second fraction and multiply. Dividing by three quarters is the same as multiplying by four thirds. The reason is that dividing asks how many of the second fraction fit into the first, and the reciprocal answers exactly that. Note that dividing by zero, or by a fraction with a zero numerator, has no answer.
What is an improper fraction and is it a wrong answer?
An improper fraction simply has a numerator larger than its denominator, such as seven fifths. It is perfectly correct and is usually preferred in algebra because it is easier to work with. Mixed numbers are preferred in everyday measurement. Both forms are shown here so you can give whichever one your question asks for.
How do I simplify a fraction to lowest terms?
Find the greatest common divisor of the numerator and denominator and divide both by it. For twelve eighteenths the greatest common divisor is six, giving two thirds. A fraction is in lowest terms when the only number dividing both parts evenly is one.
How do I handle negative fractions?
A minus sign can sit with the whole number, the numerator or in front of the whole fraction — all three mean the same value. Enter it in the whole column for a negative mixed number, or in the numerator for a simple negative fraction. The usual sign rules then apply: two negatives multiplied or divided give a positive.
Can every decimal be written as a fraction?
Every terminating or repeating decimal can, which covers everything you meet in ordinary arithmetic. The converter here handles terminating decimals by placing the digits over the matching power of ten and simplifying. Irrational numbers such as pi or the square root of two never terminate or repeat and cannot be written exactly as a fraction.
Is my working saved anywhere?
No. Every calculation happens in your browser. Nothing is uploaded, no account is needed and closing the tab clears what you typed.
Get the answer and the working
Type two fractions, choose an operation and read the result in lowest terms alongside the full solution — free, instant and with nothing to install.