Scuba Weight Belt Calculator
Estimate how much weight to wear for scuba diving.
Based on your wetsuit thickness, body composition, tank type, and water salinity.
Achieving neutral buoyancy is the foundation of good scuba diving technique. Too much weight and you drag along the bottom damaging coral; too little and you struggle to descend and waste air fighting to stay down.
General starting estimates:
- Freshwater: use 10% of body weight as a baseline
- Saltwater: use 10% of body weight + 2 kg (saltwater is denser)
Wetsuit buoyancy correction:
- Skin or no suit: 0 kg additional
- 3mm wetsuit: +2 kg
- 5mm wetsuit: +3–4 kg
- 7mm wetsuit: +5–6 kg
- Drysuit: +6–8 kg (variable — depends on undersuit)
Tank correction:
- Aluminum 80 (AL80): add 2 kg (aluminum tanks are positively buoyant when empty)
- Steel 100: subtract 1 kg (steel tanks are negatively buoyant when empty)
Body composition: Leaner divers with less body fat need more weight than average estimates. Experienced divers often find they need 1–2 kg less than beginners because they breathe more efficiently and maintain better trim.
Always verify in water before your dive: at the surface with a full breath, you should float at eye level. At 5 m with empty BCD and empty lungs, you should be neutrally buoyant.