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Dive Time Calculator

Estimate how long your air will last from tank volume, pressure, depth and respiratory minute volume (RMV).

Input

Estimate roughly how long your air will last within no-decompression limits, using tank volume, starting pressure, depth and your respiratory minute volume (RMV). Actual consumption varies widely with exertion, water temperature, experience and current, so treat the result as a rough guide only.

L
bar
m
L/min
bar

Result

Estimated dive time

~39min

39m 17s (until your reserve pressure is reached)

Dive time

~39 min

Consumption at depth

42.0 L/min

Ambient pressure

2.8 ATA

Calculation breakdown

Usable gas (surface equivalent)1,650 L
Ambient pressure (depth ÷ 10 + 1)2.8 ATA
Consumption at depth (RMV × ambient pressure)42.0 L/min
Dive time~39 min

* This is a simplified estimate that does not account for no-decompression limits (NDL), safety stops or out-of-air margins. On a real dive, keep a generous reserve and always follow your dive computer and your certifying agency's safety standards.

How it works

  • Consumption (L/min) is calculated as RMV × (depth ÷ 10 + 1). The deeper you go, the higher the ambient pressure, so the same breathing uses more air.
  • Usable air is (starting pressure − reserve pressure) × tank volume, and dividing this by the consumption at depth gives the estimated dive time.
  • RMV varies greatly between individuals and changes with exertion, water temperature, current, experience and stress. Knowing your own typical value from past logs improves accuracy.
  • Keep a generous reserve pressure (for example around 50 bar) for ascent, safety stops and emergencies.
  • This is a simplified estimate that ignores no-decompression limits (NDL), safety stops and out-of-air risk. It is not a dive plan; always follow your dive computer and your certifying agency's safety standards.