Weight for saltwater diving: what to know
Typical seawater density is around 1,025 kg per cubic metre, against about 1,000 for freshwater. Brackish water sits in between, so choose the nearer option and verify.
Worked example
For an 80 kg diver with an average build, wearing a 5 mm wetsuit and using an aluminum 80 tank in saltwater, the calculator estimates 6.5 kg (14.5 lb). Your number will differ with your body and gear, so enter your own values above and then do a buoyancy check.
Common questions
How do I weight for brackish water?
Start between the fresh and salt results, then check buoyancy.
Does the Red Sea or Dead Sea differ?
Yes. Saltier water floats you more, so you may need extra lead.
Is seawater always 1025 kg per cubic metre?
Typical seawater is about 1025, but it varies with salinity and temperature.
Do I add weight for very salty water?
Yes, a little. Saltier water lifts more, so check again on arrival.
Why is saltwater the baseline?
Most weighting advice and training assumes the sea.
Related calculators
Weight with an aluminum 80 tankWeight with a steel tankWeight for a 3 mm wetsuitHow much weight do I need?
