Rock Bottom Calculator

Dive Info

Tank Info

Your Rock Bottom bar is:

500 psi

Your actual result is psi, which is too low.
For safety, use a minimum of 500 psi instead.

Your Rock Bottom psi

psi

At a depth of , your first stop is at ft.

With a combined RMV of , you and your buddy will use cf of gas to get to the surface.

The Big Equations

Total Time × Average ATA × Combined RMV = Rock Bottom in Cubic Feet
min × ata × 2 = cf

(RB in Cubic Feet ÷ Tank Size × Rated Pressure) + optional Buffer = RB in Psi
( cf ÷ cf × psi) + psi = psi
final psi rounded to nearest 100

Let's Break It Down

(Average Depth ÷ 33) + 1 = Average ATA
( ft ÷ 33) + 1 = ATA
please read Note on Average Depth

Max Depth ÷ 2 = First Stop = Remaining Stops
÷ 2 = ft

First Stop ÷ 30 ft/min = Time to First Stop
ft ÷ 30 ft/min = min*
*rounded up to next full minute

Remaining Stops ÷ 10 ft/min = Time to Surface
ft ÷ 10 ft/min = min*
*rounded up to next full minute

Assess Time + Time to First Stop + Time to Surface = Total Time
min + min + min = min

Diver 1 RMV + Diver 2 RMV = Combined RMV
cf/min + cf/min = cf/min

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