Scuba Diving Weight Calculator

Your details

Your body weight without gear.
kg
Muscle is denser than fat: lean divers need less ballast, those with higher body fat need more.
Thicker neoprene is more positively buoyant and requires extra ballast weight to compensate.
Salt water is about 2.5% denser than fresh water, which makes you more buoyant and requires extra lead.
Aluminium tanks become buoyant as they empty; steel tanks stay near-neutral, so you need less lead with steel.
Newer divers often over-breathe and swim at a slight angle, both of which add effective buoyancy. A small extra margin helps until technique improves.
Neoprene dive boots add about 0.5 kg of extra buoyancy.
Thick neoprene gloves add about 0.3 kg.
A neoprene hood adds about 0.4 kg.
An underwater camera housing adds meaningful positive buoyancy, typically around 1.5 kg worth.
Recommended lead weightVery heavy weighting
17.2

Estimated starting ballast for neutral buoyancy

Base body contribution7.5
Wetsuit adjustment5.9
Water type adjustment1.8
Tank adjustment2
Accessories adjustment0
Unitkg
Body base7.5
Wetsuit5.9
Water type1.8
Tank2
Accessories0

Start with about 17.2 kg of lead ballast.

  • An aluminium 80 tank becomes about 2 kg positively buoyant at the end of a dive when the air is nearly gone. The calculator accounts for this so you stay neutral throughout.
  • Salt water is about 2.5% denser than fresh water. If you dive in both, remove roughly 1.5-2 kg when switching to fresh water.
  • This is an estimate. Confirm with a buoyancy check: hover at 5 m with an empty BCD, lungs at a normal mid-breath, and you should be neutrally buoyant.

Next stepKeep a dive log entry for each site noting the weight that worked best: water type, suit, and tank number. That log is the fastest way to set up correctly next time.

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