Math
Greatest Common Divisor Calculator
Find the largest whole number that divides two numbers exactly, with no remainder.
Formula
The greatest common divisor is found by repeatedly replacing the larger number with the remainder of dividing it by the smaller one, until the remainder is zero.
How it works
Enter two whole numbers. The calculator uses the Euclidean method, repeatedly taking remainders until one reaches zero. The last non-zero remainder is the answer.
FAQs
What does the Greatest Common Divisor do?
It takes the values you enter and works out the greatest common divisor for you, showing the result straight away.
What should I enter?
Enter ordinary numbers in the boxes above. If a value does not make sense for this calculation, the page will ask you to check it instead of showing a wrong answer.
Can I use the result for homework or everyday maths?
Yes. It is a general-purpose maths helper; for exam or professional work, still check the steps against your own working.