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Scuba Weight Calculator

Enter your body weight, water type, and wetsuit to estimate your dive weight.

How it is calculated

The tool gives a starting lead weight in pounds. First it takes a share of your body weight in pounds: base = body weight × 0.10 in salt water or body weight × 0.05 in fresh water. Then it adds a fixed amount for the wetsuit: none 0 lb, 3 mm 5 lb, 5 mm 10 lb, 7 mm 15 lb. The total is weight needed = base + suit addition, shown to one decimal. It does not include your tank, BCD, fins, hood or a dry suit, nor body fat or the fact that your tank gets lighter as the air is used. Treat it as a first guess for a buoyancy check at the surface, where you adjust in small steps.

Worked example

A diver weighs 170 lb and will dive in the sea in a 5 mm wetsuit. In salt water the base is 170 × 0.10 = 17.0 lb. The 5 mm suit adds 10.0 lb. The total is 17.0 + 10.0 = 27.0 lb. Switching to a fresh-water lake with the same suit halves the base to 8.5 lb, so the total drops to 18.5 lb. With a 7 mm suit in fresh water the total would be 8.5 + 15 = 23.5 lb. The tool reports the weight needed, the base weight and the suit addition separately.

Try this example →

Common mistakes

  • Entering body weight in kilograms. The field is in pounds, so 77 kg must be entered as about 170, otherwise the weight is far too low.
  • Reading the result in kilograms. The answer is in pounds, so 27 lb is roughly 12 kg of lead.
  • Selecting salt water for a lake dive, or the reverse. Fresh water needs about half the base weight, so the wrong choice leaves you either too light or overweighted.
  • Treating the figure as final. Tank type, other equipment and your own body composition move the true value, so check at the surface with a near-empty tank and adjust.
  • Using the tool for a dry suit. Only the four wetsuit choices (none, 3, 5 and 7 mm) are covered, and any other garment adds nothing.

About this calculator

A diver in a wetsuit is naturally buoyant — the neoprene traps air that floats, and salt water is denser (and more buoyant) than fresh water — so extra lead is worn to descend and hold a controlled, neutral hover at depth. This calculator's starting estimate takes 10% of body weight in salt water, or 5% in fresh water (which is less buoyant), as a base — enter your weight in pounds — then adds 5, 10 or 15 lb for a 3, 5 or 7 mm wetsuit (thicker neoprene traps more air and needs more lead).

Too little weight leaves a diver unable to descend or hold a safety stop; too much wastes air fighting negative buoyancy and strains the back. Scuba instructors, dive shops and divers themselves use a starting estimate like this before fine-tuning with an actual buoyancy check at the surface, since body composition, exposure suit, tank material and gear all shift the ideal number.

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