Scuba Air Consumption (SAC) Calculator
Calculate Surface Air Consumption (SAC) and Respiratory Minute Volume (RMV) to plan safe recreational dives.
About
Safe diving requires precise gas management. Knowing your Surface Air Consumption (SAC) rate allows you to predict how long a tank will last at any depth, transforming a guess into a mathematical plan. This tool calculates your breathing efficiency based on tank usage, depth, and time. It is vital for planning deep dives where air volume becomes the limiting factor before decompression limits, helping divers avoid "low on air" emergencies.
scuba diving
gas planning
SAC rate
RMV calculator
dive safety
Formulas
The calculator determines the RMV (Respiratory Minute Volume) adjusted to surface pressure:
SAC = (Pstart − Pend) × Vtankt × (1 + d10)
Where d is average depth (meters) and t is time (minutes).
Reference Data
| Variable | Symbol | Standard Value |
|---|---|---|
| Surface Pressure | Patm | 1 bar / 14.7 psi |
| Start Pressure | Pstart | 200 bar / 3000 psi |
| Safe Reserve | Pres | 50 bar / 500 psi |
Frequently Asked Questions
An average recreational diver consumes about 15-20 Liters/min (0.5-0.7 cu ft/min). Experienced divers with good buoyancy may drop to 10-12 L/min.
No. This tool calculates *Gas* limits. You must always cross-reference your dive time with dive tables or a computer to ensure you stay within NDLs for nitrogen absorption.
The tool supports both. In Imperial mode, it calculates based on Tank Rated Capacity (cu ft) and Rated Pressure (psi) to determine the Baseline Factor.