Rule-of-thumb starting lead estimate based on suit, body weight, water type and cylinder. Always verify with a buoyancy check at the surface.
About this tool
Gives a starting lead/ballast estimate from your exposure suit, water type and cylinder — a place to begin, not a substitute for a proper weight check.
Enter body weight, suit, salt/fresh water and cylinder type.
A rule-of-thumb estimate is shown as a small range in kg and lb.
Fine-tune with the ± control, then confirm with a buoyancy check at the surface.
Diver & equipment
Estimated lead
6.9 – 8.9
Lead (kg)
7.9 kg
Central
15.2 – 19.6
Lead (lb)
17.4 lb
Central
✓Starting estimate — always confirm with a proper buoyancy check at the surface.
Rule-of-thumb based on suit type, body weight, water density and cylinder buoyancy near empty. Results vary with body composition, equipment and diving style — validate in water before diving.