MATH

Greatest common divisor calculator

Find the largest integer divisor shared by two numbers.

01 / INPUTS

Your numbers

02 / YOUR RESULT
6
Greatest common divisor

Default inputs are examples. Change them to match your situation.

How to use this calculator

Find the largest integer divisor shared by two numbers. Enter first whole number, second whole number. The result updates when you change an input. To compare two sets of inputs, save scenario A, then enter the second set; the result panel shows the difference.

Formula and limits

The Euclidean algorithm repeatedly replaces (a,b) with (b,a mod b). GCD(0,0) is not defined here.

Worked example

The following example uses the calculator’s starting values. It is an illustration of the method, not a recommended target.

InputExample value
First whole number48
Second whole number18

Greatest common divisor: 6

Interpreting your result

Use consistent units when a calculator asks for lengths or areas. Negative inputs are accepted only where the operation supports them. Display rounding does not change the underlying formula.

Comparing alternatives

Save the first result as scenario A, then change one input. The comparison shows the numeric difference; it does not label either result as better. Choose inputs that describe realistic alternatives. Values shown on screen are rounded, so calculations from rounded intermediate results may differ slightly.

Background reading

OpenStax Algebra and Trigonometry. This is a subject reference, not an endorsement or independent review of Calcaven.

Implementation updated September 25, 2026 · How we check calculations