Does anyone know how to figure out how many carbs a person should have per day?

everyone is diffrent but if you start off at 2 weeks with 20g as Dr. Atkins suggest and then ad 5 grams back until you stop loosing that is your critical carb level (CCL) Hope that helps

If you are doing one of the published plans, they each tell how to start and how to do that plan.

You are doing "my own" plan so I don't know what that entails. it also is a bit puzzling to look at your stats and guess that you may want to lose 48 pounds despite what it says.

Atkins Induction starts at 20 grams of carbs per day. Protein Power starts at either 35 gm or 55 gm. South Beach and other semi LC plans are considerably higher.

The truth is that people don't "need" ANY carbs at all. As long as a person eats protein and fat, they can live just fine. The Eskimo/Inuit have done that for centuries. In the 1930's the very athletic and fit Arctic explorer, V. Stefansson, experimented on himself by eating nothing but meat for one year. He lost only 6 pounds and was in fine health at the end of the year. But of course, he didn't need to lose any weight. (This is all in Dr. Atkins' books in much greater detail.) So he didn't "need" carbs either.

If you choose a plan, perhaps someone can give a more definitive answer. Up at the top of the page, click on Plans in the green stripe for some short overviews of many LC plans. If you find one that is kind of like one you envision for yourself, then you'll find the answer you need.