So say you have 5 parameters for a product.

Parameter 1 has 5 choices, Parameter 2 has 7 choices, P3 has 2 choices, P4 has 3 choices and P5 also has 3 choices.

To find the total number of permutations possible you just multiply those numbers, so 5 x 7 x 2 x 3 x 3. Then you may have to assess if indeed every single one of those 420 options is valid. You may have to eliminate certain cases where Parameter 3 is ‘grey’ and P1 is ‘25’ for example.