Given the buoyancy of a thick wet-suit (8mm+) or dry-suit that cold water requires, we find that a good rule of thumb is 10% of your body weight plus 10 pounds.
Example: A 200lb person would need 30lbs of weight.
- When diving in warm water with a 5mm wetsuit, cut that weight in half.
- When diving in warm water with a 3mm wetsuit, cut that weight by 2/3.
Remember, these are estimates. Other factors will influence the weight you should wear such as how calm you are in your diving, your overall buoyancy control, the tank type (steel vs aluminum) and more so please consider these to be nothing more than rule of thumb estimates.