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SAC rate calculator

Work out how much gas you breathe per minute at the surface, so dives at different depths can be compared.

If you do not know the average depth, leave it empty: 65% of the maximum depth is used.

Metric units: m, bar, L, kg.

Result

SAC
12.8 l/min
Pressure used
120 bar
Depth used for the calculation
15.0 m

The form starts on example values.

How it works

Surface air consumption (SAC) is the volume of gas you breathe per minute, expressed at surface pressure. Deeper water is denser, so the same breath uses more gas at depth; dividing by the ambient pressure at your average depth makes dives at different depths comparable.

SAC = pressure used × cylinder size ÷ (dive time × ambient pressure at average depth). Your result is an average for that dive. Cold, effort, nerves and a heavy suit all raise it, so use a figure from your own recent dives and not a record low.

Track your SAC over time in Loggerfish →

The same calculations run in the Loggerfish app.