The Excel GCD function returns the greatest common divisor — the largest whole number that divides every supplied value with no remainder.
Syntax
| Argument | Description | |
|---|---|---|
number1 | Required | The first value. Non-integers are truncated to integers; negatives are not allowed. |
number2, ... | Optional | Up to 254 additional values. GCD finds the largest divisor common to all of them. |
How to use it
GCD (greatest common divisor, sometimes called the highest common factor) finds the biggest number that divides every argument evenly.
The most common practical use is reducing fractions to lowest terms: divide numerator and denominator by their GCD. GCD is the natural counterpart to LCM (least common multiple).
Coprime check: if GCD of two numbers is 1, they share no common factor — they are coprime. Useful for simplifying ratios and spotting fractions already in lowest terms.
Try it: interactive demo
Pick a GCD example to see the formula and its result.
Practice workbook
Frequently asked questions
What is the greatest common divisor?
=GCD(24,36) = 12 because 12 is the biggest number dividing both 24 and 36.Can GCD take more than two numbers?
=GCD(8,12,20) = 4, the largest number dividing all three.How does GCD help reduce a fraction?
What does GCD return for numbers with no common factor?
=GCD(7,13) = 1.Master functions like this in one day
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