# Common Factor Calculator

> List every factor that two or more whole numbers have in common, count them and find the greatest one.

Category: Mathematics · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/common-factor-calculator

The common factors of a set of numbers are exactly the factors of their greatest common factor, so they are listed from the GCF’s divisors.

Also called: Common divisors calculator.

## Inputs
- Whole numbers (default 24, 36)

## Results
- Common factors
- How many
- Greatest common factor

## Formula

```
Common factors of a, b, … = the divisors of gcd(a, b, …)
```

Where:
- gcd: greatest common divisor

## Worked example
1. gcd(24, 36) = 12.
2. The divisors of 12 are 1, 2, 3, 4, 6 and 12.
3. Each of these divides both 24 and 36, and no other number does.

**Result:** 24 and 36 have six common factors: 1, 2, 3, 4, 6 and 12.

## What the result means

Common factors tell you the ways a set of quantities can be split into equal groups with nothing left over, for example 24 and 36 items can both be packed in groups of 1, 2, 3, 4, 6 or 12.

## Assumptions and limits
- Positive whole numbers up to 10¹².

## Questions

### Is 1 always a common factor?

Yes. When 1 is the only one, the numbers are called coprime.

### How is this different from the GCF calculator?

The GCF calculator gives only the largest shared factor with Euclid’s working; this lists all of them.

## Related calculators
- [Greatest Common Factor Calculator](https://calculators.geekmidst.com/calculators/greatest-common-factor-calculator)
- [Factor Calculator](https://calculators.geekmidst.com/calculators/factor-calculator)
- [Least Common Multiple Calculator](https://calculators.geekmidst.com/calculators/least-common-multiple-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/common-factor-calculator