Broccoli (raw) per 1 cup serving has:
25 calories
0 grams fat
5 grams carbs
3 grams fiber
3 grams protein
People who eat TRUE low carb frequently deduct the fiber from the carbs so, 1 cup of broccoli has 5 actual carbs or 2 net carbs.
Since you are not seriously interested in eating low carb (under 60 grams a day) just count it at 5 carbs per 1 cup serving. Any sauces you add would increase carb count (for example: cheese, on average, has 1 carb per ounce)
Why we deduct fiber from the carb count:
Dietary fiber is the indigestible parts of plant cells. Although it is a carbohydrate, fiber does not convert to glucose and thus does not raise your blood-sugar level the way carbohydrates typically do. In fact, fiber actually slows the entry of glucose into the bloodstream. This, in turn, reduces the blood-sugar spikes that cause insulin production and encourage the body to produce and store body fat. And by slowing down foods transit time in the digestive tract, fiber helps you feel full longer, resulting in fewer food cravings.