How many days a week should I do abs to get an eight pack?

You must absolutely cut body fat to see the abdominals. The "eight pack" that you refer to is there. It is there for everyone. We need only to reduce body fat enough that it becomes visible. The question is not which abdominal exercises do you need to do and how often. This of course is relevant to the amount of thickness within the muscle itself but if that muscle is covered by a dense layer of fat it makes no difference whatsoever. This question requires a strict eating regimen to reduce body fat while at the same time a smart abdominal program to maximize the growth of the abdominal muscle bellies (hypertrophy).

Just like your other muscles, the abdominals require rest after workouts. The more important factor to focus on to let your abs show is your diet. Are you eating properly? The abdominals are used with every exercise you perform. The core forms the foundation for all movement, so, if you’re working out, you should be engaging your core with the various exercises you perform. If you are focusing strictly on the abdominals, perform 2-3 sets of 8-12 repetitions at a moderate to fast intensity. Do this 3 to 6 times per week, allowing at least one day of rest.

You probably don’t need to exercise your abdominals as much as you’d think.  Just like any other muscle group, you want to have at least one day of rest in between your abdominal workouts. The muscles need time to recover and then grow. You will be most successful if you work your abdominals 2-3 times per week and perform exercises from all planes of motion. I like to do 2-4 different exercises on the days I work my abdominals. Some examples of exercises you can pair are planks (include side planks as well to work oblique’s), ball crunches, crunches with rotation and even other core exercises like the floor bridge. With that said, diet is one of the most important factors in getting an eight pack (or six pack, etc). You must reduce body fat low enough to see the toned muscles underneath. Make sure you are creating a calorie deficit to reduce the body fat covering those toned muscles and you will achieve the look you desire.

Abdominals are just like any other muscle group (chest, back, legs etc). You need to work them as you would any other muscle.  If you want them to grow, then you must dedicate some time to them.  I would suggest doing at least 2-4 different exercises, 3 sets of 12-15 reps, 2-3 times a week. Some good ab exercises include: ball crunches, reverse ball crunches. oblique rotations, jack knives, hanging leg raise (1 and both legs) and planks. Watching your diet will help as well. Avoid processed foods, sugar added drinks and alcohol. Eatting lean meats and vegtables will also help trim away that belly fat that covers them up.