Free Tool
Pick Single Tank or Twin Set, set your cylinder volume, then save measurements as you collect them, depth, time, start pressure, end pressure. Dive Kit normalizes each one to surface pressure and shows your SAC (bar/min) and RMV (L/min) summary, ready to plug into your gas planning.
Free download, no account needed
Save measurements over time. Get an honest consumption rate.
The SAC/RMV Calculator turns raw dive data into surface consumption rates you can actually plan with. Set up your cylinder once (Single Tank or Twin Set, volume in litres or cubic feet), then add measurements as you collect them. Each measurement records depth, time, start pressure, and end pressure for a single segment.
The calculator normalizes gas consumption to surface pressure using Boyle's Law and saves each measurement to a list, keep multiple segments from a single dive (shallow phase vs deep phase), or build a history across many dives to see how your consumption improves with experience. Tap any measurement in the list to edit or delete it.
The Summary card at the bottom averages your saved measurements and surfaces the two numbers that matter for gas planning: SAC in bar/min (pressure-based, cylinder-dependent, for planning with the same cylinder) and RMV in L/min (volume-based, cylinder-independent, for comparing across tank sizes and feeding the Gas Usage planner).
Metric (bar/litres) and imperial (PSI/cubic feet) units are both supported, and you can export your measurements when you want to track them outside the app.
At depth, you breathe compressed gas. To find your surface consumption rate, the calculator applies Boyle's Law: P1 × V1 = P2 × V2. The formula is RMV = (pressure used × cylinder volume) / (time × depth pressure ratio). For example, using 80 bar from a 12L cylinder in 40 minutes at 20m (3 ATA): RMV = (80 × 12) / (40 × 3) = 960 / 120 = 8 L/min at the surface. This normalized rate is cylinder-independent, so you can use it to plan gas for any depth with any tank size.
A consumption rate you build over time, not a single-dive guess.
Record
Single Tank or Twin Set, cylinder volume, then the four numbers that matter: depth, time, start pressure, end pressure. Tap Save Measurement and it lands in your list, ready to contribute to your SAC and RMV averages.
Build a history
Saved measurements stack into a list. Tap any to edit or delete. The Summary card at the bottom averages them into SAC (bar/min, pressure-based) and RMV (L/min, volume-based), the numbers you plug into the Gas Usage planner for a realistic dive plan.
More free dive planning tools in Dive Kit.
Download Dive Kit free on iOS and Android. SAC/RMV Calculator is included, no account, no ads, no internet required.