The right weighting changes the whole dive, from comfort to safety on the stop. Overweighted, you fight the water, underweighted, you drift up unintentionally. This calculator estimates the weight suited to your setup, wetsuit, tank and dive water.
As an underwater photographer, your weighting follows different rules than a recreational diver. Your rig adds between 1 and 4 kg in water depending on the configuration, and that mass changes the equation entirely.
A wide-angle underwater photo rig (aluminum housing, two strobes, arms, and dome) typically weighs 2 to 3 kg in water. This means you need to remove lead compared to your usual weighting, not add it. The reflex of many beginner photographers is to keep the same weighting as on a leisure dive and compensate with the BCD. The result: labored finning, higher air consumption, and blurry photos from constant movement.
The right approach is to run a buoyancy check specifically with your rig. Gear up normally, hold your rig, and do the standard surface test (3-meter stop, tank nearly empty, lungs half full). If you sink, remove lead. If you float too much, add some. The difference from your weighting without a camera gives you the real in-water weight of your rig.
Our calculator factors your rig weight into the equation. Enter your configuration (housing, arms, strobes) and the calculation automatically adjusts the lead recommendation. It is a starting estimate: a real-conditions test remains essential, especially when changing destinations (the salinity difference between the Mediterranean and the Maldives easily adds 1 to 2 kg of extra lead).
Weighting depends on your body type, wetsuit, tank type and water salinity. An 80 kg man in a 5mm wetsuit with a steel 12L tank in the Mediterranean needs about 5 kg of lead. Our calculator takes all these parameters into account for a personalised result.
An overweighted diver must overinflate their BCD to compensate, making buoyancy unstable. If the BCD fails, they risk an uncontrolled ascent after dropping weights, or sinking if they cannot ditch them. The DAN (Divers Alert Network) identifies overweighting as a frequent contributing factor in diving accidents.
Salt water is denser than fresh water, increasing the diver's buoyancy. In the Red Sea (density 1.031), you will need more lead than in a lake (density 1.000). The difference can reach 2 to 3 kg depending on your weight and equipment.
Aluminum tanks become positively buoyant when empty (up to +2 kg for an AL80), unlike steel tanks which remain negative. You therefore need more lead to compensate for this positive buoyancy at end of dive, especially for the safety stop.
At the surface with a full tank and empty BCD, you should float at eye level while breathing normally. Holding your breath, you should sink slowly. At end of dive (empty tank), you should be able to hold your safety stop effortlessly. Our calculator targets exactly this balance.