Learn what Maximum Operating Depth means, how MOD is calculated from oxygen percentage and PPO2 limits, and how to apply it in real dive planning.
Read guideLearn what Nitrox is, how enriched air works, its benefits and risks, and why divers choose it.
Read guideLearn what Surface Air Consumption rate is, how to calculate it, and tips to improve your breathing efficiency underwater.
Read guidePlan your gas requirements for any dive. Know if your tank has enough gas before you get in the water.
Standard minimum reserve of 50 BAR. Widely used in recreational diving.
+5 min
longer
3,133 L
Insufficient
+5 m
deeper
3,338 L
Insufficient
Both
+5 m & +5 min
3,688 L
Insufficient
This planner calculates how much gas you need for a dive based on your breathing rate, depth, and time. It tells you whether your tank has enough gas and how long you can stay.
Your RMV (Respiratory Minute Volume) or SAC (Surface Air Consumption) rate is how much gas you breathe per minute at the surface. Use the SAC Rate Calculator to find yours from logged dives.
Gas consumption increases with depth because the air is denser. At 20m you breathe 3x as much gas as at the surface.
• Minimum Reserve (50 BAR)
Standard recreational reserve. Always surface with at least this amount for safety.
• Rule of Thirds
Use 1/3 going out, 1/3 coming back, keep 1/3 as reserve. Standard for cave and wreck penetration diving.
• Custom Reserve
Set your own minimum reserve pressure based on your training and dive conditions.
• Know your RMV rate
Track your SAC rate over multiple dives to get an accurate personal RMV
• Plan conservatively
Use a higher RMV than your average to account for currents, stress, and exertion
• Monitor during the dive
Check your SPG frequently and compare actual consumption to your plan
• Always plan for emergencies
Reserves exist for unexpected situations - never dip into your reserve gas
