GCD Calculator (Greatest Common Divisor)

The greatest common divisor (GCD) of a set of integers is the largest positive integer that divides every one of them with no remainder. For 48 and 36 that value is 12, since 12 splits both evenly and nothing larger does.

Yes. Greatest common divisor (GCD), greatest common factor (GCF), and highest common factor (HCF) are three names for the identical value. The tool computes it the same way whichever term your textbook uses.

Two is the useful minimum, but you can paste a long list and the calculator folds the Euclidean algorithm across all of them, reducing the running divisor pair by pair until one value remains.

It works from absolute values, so the GCD of -48 and 36 is 12. A divisor is always reported as a positive integer regardless of the signs you enter.

The GCD of 0 and 5 is 5, because every integer divides 0 exactly. If every value you enter is zero, the result is defined here as 0, since no largest common divisor exists.

The greatest common divisor is only defined for integers. If you type a decimal such as 2.5 or any non-numeric text, the tool shows a short message asking for whole numbers so the answer stays exact.

Yes. Commas, spaces, tabs and line breaks all work as separators, and extra separators are ignored, so pasting a column of numbers from a spreadsheet is fine.

No. The whole calculation happens locally in your browser using client-side JavaScript, so the numbers you enter never leave your device or reach a server.

Use the linked LCM calculator. The GCD and LCM are related by the identity a times b equals GCD times LCM for two numbers, so the two tools pair up naturally.