Free scuba calculator
Tank Autonomy Calculator
Estimate how long your scuba cylinder can last at a planned average depth using your SAC rate and a fixed 50 bar reserve.
SAC based50 bar reserveLive calculation
Calculator
How long will your tank last?
Enter your cylinder, pressure, SAC and planned average depth. The calculator estimates usable time before reserve and how long the reserve itself represents at that depth.
L
bar
L/min
m
Reserve pressure50 bar
Fixed reserve, matching the reference calculator.
What the result means
The calculator updates instantly from the values you enter and shows the core planning result in the dark result card.
Use conservative inputs
Use realistic values from your own diving and leave a practical margin for changes in workload, conditions and equipment.
Verify before diving
Treat this page as an educational reference and cross-check the result with your training, analysed gas and an appropriate dive-planning method.
Planning reference only. These calculators are educational reference tools, not a substitute for training, a properly configured dive computer, analysed breathing gas or an approved dive plan. Use conservative values and follow the procedures of your training agency and dive operation.