SAC rate-
RMV-
Ambient pressure-
Surface-equivalent gas used-
Breathing Gas Planning
Scuba Gas Consumption Calculator: SAC, RMV & Tank Duration
Turn a real dive into a surface consumption rate, then use that rate to estimate gas use at another depth. Metric calculations use cylinder water volume; imperial calculations use rated cylinder capacity and service pressure.
Calculator 1
Calculate SAC and RMV from a dive
Use average depth, dive time, cylinder data and the pressure you actually consumed.
Calculator 2
Gas requirement and estimated tank duration
Use an RMV you already know to estimate consumption at a constant average depth.
Gas for planned time-
Required start pressure-
Estimated time to reserve-
Planning note-
How the Math Works
SAC and RMV formulas
Ambient pressure: metric ATA = (depth in meters / 10) + 1. Imperial ATA = (depth in feet / 33) + 1.
SAC pressure rate: pressure used / dive time / ATA. SAC expressed in bar/min or psi/min depends on the cylinder configuration.
Metric RMV: (bar used x cylinder water volume in liters) / dive time / ATA.
Imperial RMV: ((psi used / rated service psi) x rated cylinder capacity in cubic feet) / dive time / ATA.
Estimated tank duration: usable surface-equivalent gas before reserve / (RMV x ATA).
Planning Limits
Real gas planning needs more than an average-depth estimate
Breathing rate changes with workload, stress, current, temperature, equipment and diver condition. Actual dive profiles also include descent, depth changes, ascent and safety or decompression stops. Technical and overhead dives require formal minimum-gas and contingency planning. Use this page to understand consumption and make estimates, not to replace the gas-planning procedures from your training.