How many grams of carbs should you eat a day?

Here's a popular question. I weigh "this much" and I'm "this tall", I workout like "this" and I'm looking to get "these results", how many grams of carbs should I eat a day? Some people, websites and magazines will tell you to take your body weight and multiply it by your height, divide that by the number of days a week you workout, then add the grams of protein you eat every day, take this number and divide it by the 3rd digit of your telephone number, then pick your favorite number between 1 and 1000 and add that in too, then do the magic carb dance and your final total is the number of carbs you need to eat every day.
Okay, maybe that isn't the exact carb formula, but it is something like that. Anyway, my method for figuring out how many carbs you need to eat each day has nothing to do with math formulas and won't require you to have a calculator handy. It is actually quite easy.
I'm sure everyone knows by now that if you want to lose weight, eating a lower number of carbs seems to help. (For more information, go here: low carb diet and foods) And if you want to gain weight, you should eat a higher number of carbs. We all know this, but people want to know the EXACT number of carbs they need to eat. Here's my way of figuring it out. Throughout this website I try to stress the point that you should listen to your body. Is your workout routine not giving you results? The fact that you aren't getting results with that routine is your body saying "this isn't working, change it!" In my opinion, your diet, in this case carbs, is no different.