Why divers need weight
Most divers are naturally buoyant, and exposure suits add even more buoyancy, so divers wear lead weight to be able to descend and hold a controlled, neutral buoyancy underwater. The right amount depends on body weight, what you’re wearing, the water type, and even your tank.
How this estimate is calculated
This calculator applies the general rule-of-thumb guidelines commonly taught in entry-level diver training: a percentage of body weight for the exposure suit you’re wearing (thicker neoprene needs more weight to offset), a small extra allowance for salt water (which is more buoyant than fresh water by about 2.5%), and a tank adjustment (aluminum tanks tend to become more buoyant as air is used, so slightly more weight is added; steel tanks are already negatively buoyant, so slightly less is needed).
- No suit: no extra weight allowance
- 3mm wetsuit: about 5% of body weight
- 5mm wetsuit: about 8% of body weight
- 7mm wetsuit or semi-dry: about 10% of body weight
- Drysuit: about 15% of body weight
This is only a starting point — always fine-tune your actual weighting with a proper buoyancy check at the surface and under a certified instructor’s guidance before diving.