Scuba diving calculators

Enter the geometry of a dome port and your lens’s minimum focus distance to check whether the lens should focus on the distant-subject virtual image. The calculation uses a thick-wall, paraxial model rather than the usual 4r shortcut.

Enter up to four constant-depth gas segments to estimate PPO2, CNS oxygen clock loading, OTUs, REPEX allowance, and remaining CNS time at the last segment PPO2.

Enter an analyzed scuba mix and planned depth to estimate gas density, oxygen partial pressure, equivalent narcotic depth, and the maximum depth allowed by your density and PPO2 limits.

Enter each diver’s back-gas cylinders, starting pressure, and RMV to find the matched turn pressures for an equal-time out-and-back penetration. The result identifies the limiting donor and checks whether ordinary pressure thirds would leave a sharing-gas shortfall.

Enter the depth, stressed breathing rates, ascent plan, and cylinder size to estimate the minimum gas reserve for a shared-gas ascent.

Enter the planned depth, END limit, cylinder pressure, and any residual gas to get a trimix target and an additive partial-pressure fill plan.

Enter your sensor, lens, distance, and water type to estimate what a rectilinear lens sees through a flat port. The reverse calculation finds the focal length that frames a known subject width at that distance.