How do I check for possible combinations?

Im trying to make the computer automatically check for how many words that can be created with 6 letters.

I have dictionaries that contain 3 letter, 4 letter, 5 letter and 6 letter words. The computer randomly gives 6 letters and I would like to automatically check how many of the words in my dictionaries that can be created with those 6 letters.

What would be a good way to do this? Ive tried to make a loop that creates all possible combinations that can be made with the 6 letters and find matches in the dictionaries, but i dont know if that is a very good solution.

Any ideas or tips are welcome!

If you've made a loop that creates all possible combinations of words that can be made with 6 letters then I think you've already done it? Or did you mean tried and failed..