Reading the output¶

After you tap Calculate dive plan, the app produces a stack of cards covering every aspect of the planned dive. This page walks through each one.

Top-line metrics¶

The header strip shows six numbers at a glance:

Metric	Meaning
Max depth	Deepest point of the dive
Avg depth	Average depth across the entire dive (descent + bottom + ascent + deco)
Run time	Total dive duration, surface to surface
TTS	Time to surface from the start of the ascent (details)
CNS	Cumulative CNS oxygen toxicity percentage
OTU	Cumulative oxygen tolerance units

Any value that exceeds a recommended limit becomes a red warning in the Critical warnings banner at the top.

Critical warnings¶

If the plan has problems, a banner appears between the metrics and the charts. Common warnings:

Gas density above 5.2 g/ℓ — switch to a more helium-rich mix
Gas density above 6.2 g/ℓ — hard limit exceeded; do not dive this profile
Gas shortfall — total used gas exceeds cylinder fill
Rock bottom IMPOSSIBLE — the required reserve is larger than the cylinder
CNS approaching limit
PPO₂ exceeds maximum at depth — bottom gas is too rich for max depth
Hypoxic at surface — bottom gas can't be safely breathed at shallow depths

Any red warning is a sign that something is structurally wrong with the plan. Yellow warnings are advisory.

Deco plan card¶

Total deco time¶

The sum of all decompression stop durations. Doesn't include ascent time between stops or the final ascent.

TTS at ascent start¶

TTS measured at the moment you leave the deepest planned segment.

Deepest ceiling¶

The deepest depth at which the leading tissue compartment reaches GF Lo on direct ascent. The first deco stop will be at or just shallower than this.

Dive profile chart¶

A graphical depth-vs-time plot:

Blue line — actual depth profile
Solid red line — GF ceiling (the deepest you can be without exceeding GF Lo, evolving as tissues off-gas)
Dashed faded-red line — M-value (raw Bühlmann ceiling, GF Hi = 100)
Dashed grey line — average depth

The shape of the dive narrative is visible at a glance: descent slope, bottom hold, stepped ascent through stops, and the gradient between the depth line and ceiling line — that gap is your safety margin.

GF99 chart¶

Tissue saturation as the dive progresses:

Green areas — off-gassing (positive GF99)
Red areas — on-gassing (negative GF99)
Solid green line — GF99 over time
Blue dashed line — target GF99 (= GF Hi / 2)
Red dashed line — GF Hi limit

See Tissue saturation & GF99 for what each curve means.

Runtime schedule¶

The detailed minute-by-minute plan as a table. See TTS & deco stops for symbol meanings and row interpretation.

Each row gives:

Symbol — ↘ ↗ → ⊙ (descending, ascending, holding, gas switch)
Depth (m)
Runtime — total elapsed time
Duration — segment duration (+ prefix)
Gas (OC) or Loop SP / Dil PPO₂ (CCR)

Deco stop rows are tinted light green. Gas-switch marker rows are tinted light blue.

Not seeing a stop at every depth (e.g. 18 m then 9 m), or unsure when the slower deco ascent rate applies? See When a stop is skipped and Ascent rate during decompression.

Gas plan card¶

Bar chart¶

One horizontal bar per cylinder showing:

Blue (Used) — gas consumed during the planned dive (matches the "Used (bar)" column in the table below)
Red (Reserve) — rock-bottom reserve still preserved in the cylinder
Grey (Unused) — surplus beyond the reserve

If a cylinder's Red segment is smaller than its rock-bottom requirement, the dive overdraws the reserve — increase fill, larger cylinder, or reduce dive time.

Cylinders table¶

Column	Meaning
No.	Position in the cylinder list
Mix	O₂/He
Size (ℓ)	Cylinder volume
Usage (bar)	Fill → remaining (used)
Used (ℓ)	Total litres consumed

Limits table¶

For each gas, the depth where it's breathed and the corresponding density, EAD/PPO₂, and warning levels:

Depth	Mix	Density	PPO₂
75 m	16/58	5.14 g/ℓ	1.34

Density coloring: green/black ≤ 5.2, orange 5.2–6.2, red > 6.2.

Rock bottom & TTS card¶

Rock bottom reserves¶

One per bottom and travel gas cylinder. Shows the minimum bar pressure that must remain at the end of the dive — see Rock bottom.

Ascent trigger¶

A target TTS field you can fill in for your reference: "Start your ascent when either your dive computer shows TTS ≤ your target, or your gas reaches the minimum reserve — whichever comes first." Doesn't affect the calculation.

Contingency plan toggles¶

The Deeper +N m and Longer +N min buttons at the top of the Deco plan card show a contingency profile:

Deeper +3 m — re-runs the plan with all segments 3 m deeper (default; configurable in settings)
Longer +3 min — re-runs with all bottom times 3 min longer (default; configurable)

The deco plan, gas usage, and warnings update for the contingency scenario. Useful for "what if I overshoot?" planning.

CCR-specific additions¶

In CCR mode, the cards expand with rebreather-specific information:

Diluent PPO₂ in the runtime schedule
Loop density in the Limits table
Bailout sufficiency check and the open-circuit bailout schedule (independent bailout mode)
Maximum loop TTS, bounded by bailout gas only

Oxygen consumption and scrubber endurance are not shown — see Oxygen & scrubber.

See CCR overview for details.

Once a plan is calculated, the share menu lets you:

Copy a link that opens the same plan in a buddy's browser
Generate a print-ready PDF with the same charts and tables
Send a plain-text briefing for Messages, email, or notes

See Sharing & backup.