A beginner will benefit from starting to learn with a hoop at least as big as the size suggested here.

Please Note: Whilst you measure around the perimeter of your waist, the hoop size is actually given as the diameter of the hoop.

After trying the size of hoop that is recommended here, if you still cannot keep the hoop spinning around your body, it is suggested that you should once more study the correct technique in this video: "How to Hoop" and if after that you are still struggling then you should try a hoop maybe 4 to 6 inches larger.