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The planner Plus

The maths,
done honestly.

Bühlmann ZHL-16C with gradient factors and full trimix, validated against Subsurface. It will never quietly bend an impossible plan — it surfaces it as an error, where you can see it.

Plan a diveGF 40/85
Depth
45m
Bottom
25min
Tx 18/45EAN50O₂
Runtime48 min
First stop21 m
Total deco23 min
No-fly clears18 h
The model

Bühlmann ZHL-16C, with gradient factors.

The same algorithm the serious tools use — sixteen tissue compartments, nitrogen and helium throughout, with gradient factors you set yourself. Plan a single dive or a staged technical descent with multiple gases and deco mixes.

  • Full N₂ + He trimix, not nitrox-only
  • Gradient factors (e.g. 40/85) under your control
  • Multiple bottom and deco gases, switched at depth
Decompression scheduleTx 18/45
First stop
21m
Deco
23min
Runtime
48min
Plan a diveCheck
Depth
60m
Gas
EAN32
Gas not breathable at depth

EAN32 reaches a PO₂ of 2.1 bar at 60 m — above the 1.6 limit. Choose a hypoxic mix or reduce the depth.

Max operating depth33 m
The honesty

It tells you when a plan won't work.

A planner that silently produces a number for an impossible dive is dangerous. ScubaOS refuses to — an unbreathable mix, a missing gas, an ascent the model can't honour are surfaced as a clear, labelled error, with the limit that broke it. Never colour alone; always an icon, a label and the offending value.

  • PO₂ and MOD limits checked for every gas
  • Impossible schedules raised, never quietly bent
  • Validated against Subsurface, with CI that fails on divergence
Recreational ↔ technical

Simple by default. Technical when you need it.

The planner adapts to the diver, not the other way round. In recreational mode it's a clean no-stop slate; switch to technical and gradient factors, multiple gases, and the full deco schedule appear — the same app, revealing depth, never a different one.

No-stop slate

Depth, time and gas in, no-decompression limit and turn pressure out. Everything a rec dive needs, nothing it doesn't.

Full deco plan

Gradient factors, gas switches, runtime, stop-by-stop schedule and gas consumption per cylinder.

Honest by design

The hard limits are always on. The model never hides a problem to give you a tidier number.

In detail

Under the hood.

Algorithm
Bühlmann ZHL-16C with gradient factors, full nitrogen + helium (trimix).
Gases
Air, nitrox, normoxic and hypoxic trimix; multiple bottom and decompression gases with switches at depth.
Outputs
Runtime, first stop, stop-by-stop schedule, total deco, gas use per cylinder, no-fly time.
Limits enforced
PO₂ ceiling, MOD per gas, hypoxia at depth — surfaced as labelled errors, not silently bent.
Validation
Compared to Subsurface reference schedules in an automated harness; CI fails on divergence.
Determinism
The deco engine is pure and deterministic — the same plan always produces the same schedule.

No software can guarantee a safe dive. ScubaOS is a planning aid — always dive within your training and trust your certified dive computer in the water.

Plan your next dive.

The full decompression planner is part of Plus — a one-time purchase. Quick-slate planning is free.