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Add fractions calculator

Add two fractions with any denominators. Enter the numerators and denominators for each fraction and this calculator finds the common denominator, adds the fractions, and simplifies the result. Step-by-step working is shown so you can see exactly how the answer was reached. All calculations run locally in your browser.

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How it works

For addition and subtraction, the tool finds the least common multiple (LCM) of the two denominators, converts both fractions, and adds or subtracts the numerators. For multiplication, numerators and denominators are multiplied directly. For division, the second fraction is flipped (reciprocal) and multiplied. Results are simplified using the greatest common divisor (GCD) via the Euclidean algorithm. All arithmetic runs in JavaScript in your browser.

Processing runs in your browser

All calculations happen locally in your browser tab. Our servers are not involved at any point.

Related operations

For converting a fraction into a percentage, try the percentage calculator. To switch between metric and imperial measures, use the unit converter. For translating numbers into Roman numerals, see the Roman numeral converter.

Frequently asked questions

How do you add fractions with different denominators?
Find the lowest common denominator (LCD) of both fractions. Convert each fraction to an equivalent fraction with the LCD. Add the numerators and keep the LCD as the denominator. Simplify by dividing both parts by their greatest common divisor (GCD).
What is a lowest common denominator?
The lowest common denominator (LCD) is the smallest number that both denominators divide into evenly. For example, the LCD of 1/4 and 1/6 is 12, because 12 is the smallest number divisible by both 4 and 6.
How do I simplify a fraction?
Find the greatest common divisor (GCD) of the numerator and denominator, then divide both by it. For example, 6/8: GCD is 2, so 6/8 simplifies to 3/4.
Is my data sent to a server?
All calculations run locally in your browser using JavaScript. No data is sent to our servers.

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