Common Factor Calculator
Quickly calculate the common factors of two or more integers
Paste values that use your local number separators and get accurate results immediately. This calculator is free and works on any device.
Number format
Choose how results are displayed and which thousands and decimal separators are accepted in the inputs. Values must be integers; decimal notation is accepted only when the fractional part is zero.
Results
Enter at least two numbers
How to use the calculator
Enter the numbers
Enter two or more integers in the fields. You can use separators such as commas or spaces according to the selected number format, for example 1,000 or 1.000. You can enter up to 10 numbers.
Calculate automatically
After you enter at least two numbers, the calculator automatically finds their greatest common divisor (GCD) and all common factors. There is no Calculate button to press.
Review the results
The results panel displays the numbers you entered, their greatest common divisor, and a list of every common factor. Select a common factor to copy it to the clipboard.
What is a common factor?
A common factor is an integer that divides two or more integers without a remainder. The greatest common divisor (GCD) is the largest integer that divides all of the numbers.
Examples of use
Example 1: Simplifying fractions
Find the greatest common divisor of a numerator and denominator to reduce a fraction to its simplest form. For example, the GCD of 24 and 36 is 12, so 24/36 reduces to 2/3.
Example 2: Dividing items into groups
Use the GCD to split different quantities into an equal number of groups. For example, 48 apples and 60 oranges can be distributed evenly among at most 12 baskets.
Example 3: Designing tile layouts and patterns
Use room dimensions, such as 240 cm × 180 cm, to find the largest square tile size, 60 cm, that fits without cutting.
Example 4: Comparing schedules
Compare repeating event intervals, such as every 6, 8, and 12 days. Their greatest common divisor is 2 days.
Example 5: Manufacturing and production planning
Calculate the largest number of equal sets that can be made from different quantities of materials. For example, quantities of 120, 180, and 240 have a GCD of 60, so they can form 60 equal sets.
Frequently asked questions
Q1: Can I enter negative numbers?
A: Yes. The calculator uses absolute values when finding common factors.
Q2: What happens if I enter a decimal?
A: A non-integer value is reported as invalid. Decimal notation that still represents an integer, such as 12.0, is accepted.
Q3: What happens when I change the number format?
A: The display format and input parsing both change. For example, in the 1.234,56 format, the period is treated as the thousands separator and the comma as the decimal separator.
Q4: How many numbers can I enter?
A: You can enter up to 10 numbers. Use the Add another number button to create more input fields.
Q5: What does it mean when 1 is the only common factor?
A: If 1 is the only common factor, the entered numbers are relatively prime and share no factor greater than 1.