Depending on the quality of the mixture placed in the composter you should have a compostable mixture at the bottom of your bin after 6 to 12 months.
Note: turning over and mixing your composter will make the decomposition faster and more even.
A wormery
With worm bin composting, the more well established the worms are the quicker they will be able to process food scraps. In the beginning it may take 3 months to make your own soil, but once the worms are established the turn around could take less than a month.