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.
How Scuba Weight Belt Requirements Are Calculated
Proper weighting is one of the most important skills in scuba diving. Too much weight wastes air fighting to stay up; too little and you can’t descend or control buoyancy at depth.
Buoyancy Calculation:
Net Buoyancy = Water Displaced Weight − Diver System Weight
To be neutrally buoyant: Net Buoyancy = 0
Starting Weight Estimate (Rule of Thumb):
Base Weight (kg) = Body Weight (kg) × 0.10
Then add/subtract for:
- Wetsuit (3mm): +1–2 kg
- Wetsuit (5mm): +2–4 kg
- Wetsuit (7mm): +4–6 kg
- Drysuit: +6–10 kg (varies greatly by undersuit)
- Saltwater vs freshwater: salt water is denser, need 2–3 kg less weight in freshwater
- Steel tank vs aluminum: aluminum 80 is positively buoyant when empty (+1–2 kg adjustment)
Worked Example: 70 kg diver, 5mm wetsuit, saltwater, aluminum tank:
- Base: 70 × 0.10 = 7 kg
- 5mm wetsuit: +3 kg
- Aluminum tank (positive when empty): +2 kg
- Starting estimate: 12 kg
Fine-Tuning Procedure: Perform a buoyancy check at the surface: with a full breath, you should float at eye level. Empty your BCD completely. If you sink, remove 1 kg. Repeat until you float at eye level with lungs full, and gently sink when you exhale.
Safety Note: Never remove your weight belt underwater. Integrated weight systems should have a quick-release on at least one pocket.