Inputs

Units:

Imperial Metric

Dive plan

Depth at gas-share emergency

Number of divers sharing

RMV (per diver, surface)

cu ft/min

Working RMV (resting RMV is ~0.5 cu ft/min ≈ 14 L/min).

Stress factor

2× is a common conservative default.

Problem-solving time at depth

min

Ascent rate

ft/min

Include safety stop (3 min @ 15 ft / 5 m)

min

Tank

Rated volume (per tank)

cu ft

Rated pressure

psi

Number of tanks

Results

Surface gas required

—

Reserve pressure (rock-bottom)

—

turn back at this pressure

Phase breakdown

Phase	Time	Avg ATA	Gas (surface)

How to use this: “Reserve pressure” is the minimum tank pressure that always keeps enough gas for a worst-case shared ascent. Plan to turn the dive when your tank reaches this pressure. Reserve is rounded up to a practical value.