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
Lead (kg)
6.9 – 8.9
Central
7.9 kg
Lead (lb)
15.2 – 19.6
Central
17.4 lb
✓ 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.