How to Calculate Diving Weight

Typical "Soft" Weights Used in Weight Integrated BCs

Calculating the proper weight to use while diving is as important as choosing the right size dive mask. If it is not enough weight, you will not be able to submerge. If it is too much, you will sink quickly which in some instances can be life threatening. If you have selected the ideal weight, you can maintain neutral buoyancy in the water while submerged.

Things You'll Need

• Bathroom scale
• Dive weights
• Weight belt or weight-integrated buoyancy compensator (BC)

Instructions

1. Weigh yourself. It is vital that you accurately record your own weight.

2. Calculate the "mean" weight. You should use 6 to 8 percent of your body weight for your dive weights if you are diving in fresh water. If you are diving in salt water, you should use 8 to 10 percent of your body weight. For example, for salt water, multiply .08 to .10 times your body weight. A 150-lb. person diving in salt water, then, should use 12 to 15 lbs. of weights.

3. Weigh your equipment. Most aluminum tanks are positively buoyant, as is an inflated BC and your wet suit (if you are wearing one). To determine the the dive weight of the equipment, multiply it by .08.

4. Add the two amounts of weights you calculated in steps 2 and 3. This is the amount of weights you will need to add to your weight belt or weight-integrated BC.

5. Check your buoyancy upon entering the water. If you have the proper amount of weight, you should gradually descend as you let air out of your BC. If the descent seems too rapid, immediately refill the BC with air, surface, and offload some weight. If the descent is too slow, or you don't sink at all, add more weight.

Tips & Warnings

• Calculating approximate weights for diving is exactly that: an approximation. Utilize these numbers as a good starting point, and then add or subtract weight as necessary to achieve neutral buoyancy. There are three major factors other than body weight that will affect the amount of weight you need: (1) whether the dive is in fresh or salt water; (2) whether you are wearing a wetsuit (a thicker suit will require more weight); and (3) the type of scuba tank you are using. After extensive diving, you will "get a feel" for the amount of weight you need given the conditions and your equipment and you will no longer need to calculate it.

References

• National Association of Underwater Instructors
• Professional Association of Diving Instructors