SAC Calculator
Find out how much gas you breathe per minute, using the numbers from a dive you've already done.
Results update as you type.
What your gauge showed before the dive.
What your gauge showed when you surfaced.
Water capacity of the tank. Most rental tanks are 12 L.
From your dive computer or log.
The average depth from your dive computer, not the maximum.
SAC rate
Within limitsYou breathe 14.4 litres per minute at the surface, which is about 36 L/min at 15 m.
- Gas used
- 1800 L (150 bar)
- Pressure rate on this tank
- 1.2 bar/min
- Consumption at 15 m
- 36 L/min
Was this calculator useful?
These tools are educational planning aids; they are not a substitute for dive training, current printed tables or a dive computer. Verify results against your training and always plan within the limits of your certification.
How to use the SAC calculator
- 1
Take the numbers from a dive you've already done: start and end pressure on your gauge, your tank size and the dive time.
- 2
Enter the average depth from your dive computer, not the maximum depth.
- 3
Read your SAC rate and see where it sits on the scale. Work it out for a few dives to find your real average.
What the results mean
SAC (surface air consumption) is how many litres of gas you would breathe per minute at the surface. Because it removes the effect of depth, you can compare dives and plan future ones with it.
Deeper, you breathe more: multiply your SAC by the absolute pressure. At 10 m (2 bar) a SAC of 15 L/min becomes 30 L/min.
Many recreational divers fall between 15 and 25 L/min. Stress, cold, current and poor buoyancy push it up; relaxed breathing and good trim bring it down.