Deco Planner

What it is

The Deco Planner builds a complete decompression schedule for a planned dive: descent, time at each level, ascent, every required stop, and the gas you will breathe along the way. It runs the Bühlmann ZH-L16C algorithm with gradient factors, so its output lines up with established planners like MultiDeco.

It handles both open circuit (OC) and closed circuit rebreather (CCR) dives, multiple gases with automatic switching on ascent, repetitive dives that carry tissue loading forward, contingency scenarios, and sharing a plan with your buddy by link or QR code.

The Deco Planner is a Dive Kit Pro feature. Without Pro you can open a plan a buddy shared and read every output, but you cannot create or edit one. A shared plan opened without Pro shows a Read-Only Plan banner with an Unlock Dive Kit Pro button, and it is not kept when you leave the screen.

The rest of this guide

This page is the tour: how to start a plan, how to describe the dive, and how to get around the screen. Four more pages are the reference.

Page	What it covers
Gases in the Deco Planner	Every field in the gas sheet, MOD and the PPO₂ bands, a reserve for one cylinder, automatic gas switching, and what happens when a cylinder runs out
Deco Planner settings	Every setting row in order, with its range, default, and whether it moves your stops
Reading a deco plan	The stats pill, the profile graph, the stop table, the Gas Consumption card, the bottom time finder, and every warning
Contingencies and plan modifiers	The scenario tabs, building your own, and the four plan modifiers

Rebreather divers should also read CCR diving, which covers the rig, setpoints, diluent switches and bailout end to end.

The screen, top to bottom

A plan is one scrolling screen in three parts. Knowing which part you are in makes the rest of this guide easier to follow.

1. The inputs. Four cards, in this order: Dive Profile (your levels), CCR (the rebreather rig, on every plan whether or not you use one), Gases, and Settings. On a phone they open collapsed; on a tablet they start expanded.
2. The scope block. Three rows that say which version of the plan you are looking at: the scenario tabs, the CCR view chips (rebreather plans only), and the Modifiers line. This block sticks to the top of the screen once you scroll past it and releases when you scroll back up, so a stop table thirty rows down never loses the plan it belongs to. On a tablet, where the results are the long column, it pins above them for the same reason.
3. The results. The difference pills, the dive profile graph, the stop table, the Gas Consumption card, and Plan Next Dive.

A floating stats pill sits above the tab bar the whole time with runtime, time to surface, CNS, OTU, gas density and the plan’s status. On a tablet in landscape the inputs and the results become two columns that scroll independently.

The planner recalculates as you edit. There is no calculate button.

Plan a dive

The dive profile

The dive is described as one or more levels, each a depth and a time. The Dive Profile card lists them in the order you dive them. Collapsed, the card header shows one chip per level, like 45m/20".

For a square dive, use a single level. For a multi-level profile, add a level per segment, deepest part first. Add Level seeds the new row 6 m (20 ft) shallower than the last one, for 10 minutes, on Auto gas. Long-press a row and drag to reorder: the order of the levels is the order of the dive, so reordering changes the schedule.

The trash icon on a row deletes it without a confirmation. It disappears when only one level is left, because a plan needs a level.

Reading a level row

Each row packs the whole level into one line, with tags underneath.

What you see	What it means
45m and 20min	The level’s depth and time. A swap icon instead of a time means a travel stop (zero minutes)
A gas name, or SP 1.3	The gas that level breathes after Auto has resolved it, or the loop setpoint on a rebreather. A rebreather level riding a dilout reads SP 1.3 · 18/30
An OC badge	On a rebreather plan, this level is breathed open circuit rather than on the loop
A small accent dot	You pinned a specific cylinder to this level rather than leaving it on Auto
A triangle, circle or blue i	This level has an issue. Open the level to read it under Issues at this level
PPO2 1.4	The oxygen partial pressure at that depth on that gas, always in bar. It tints yellow or orange as it climbs
END 32m	The equivalent narcotic depth, shown only when it is shallower than the level, so it never appears on air or any helium-free mix
ρ 5.1 g/L	The gas density at that depth, tinted against your warning and critical thresholds
NDL 12min	The no-stop time left at that level. Reads NDL 12min · last stop required when the plan still has to pause on the way up. See below

Between two rows that change gas, a small indicator names the switch and, when you have set a gas switch time, what it costs: 21/0 → 50/0 (+2 min).

The NDL tag on a level

A level row can carry an NDL tag with the minutes of no-stop time left there. It is computed at your plan’s GF High, the same conservatism the engine applies on the bottom, so it reads shorter than an agency table. Five minutes or less turns the tag yellow.

A dive can show no-stop time on a level and a stop in the table below it at the same time, and both are right. A profile that touches the GF Low line is routed through the last stop and held there by the minimum stop rule, even when its ceiling is zero the whole way up. That stop is required, but it is not decompression, so the level keeps its no-stop figure and the tag adds last stop required to say which kind of stop the table is showing. When a ceiling really does hold you somewhere, the tag carries no such note.

It is deliberately absent more often than it is there. A level that already owes a stop has no no-stop time left, so nothing is shown rather than a 0. A level shallow enough to sit there indefinitely shows nothing either, because “no practical limit” is not a figure to plan against. On a bailout view the engine reports nothing at all and the tag stays away. The tag always describes the base plan, not the contingency tab you happen to be on; contingency tabs carry their own NDL difference pill instead.

Which gas a level breathes

Open a level and the Gas row offers Auto first, then CCR on a rebreather plan, then one chip per cylinder in your gas list.

Auto is the default on every new level and is what most plans want. It takes the highest-PPO₂ gas whose maximum operating depth covers that level, and the sheet says which one it picked and why, in a line under the chips. Auto also looks ahead on the initial descent: while each level is deeper than the one before, it only picks a gas you can keep breathing to the bottom of that descent, so a shallow first level (a bubble check, say) never grabs a deco gas on the way down. Once the profile steps back up, every later level, including a shallow interval between two deep excursions, keeps the richest safe gas. If no gas in your list covers both depths, as on hypoxic trimix dives, Auto falls back to the richest gas that is safe at the level itself.

Pick a cylinder chip instead and you pin that level to that gas. The row then carries the accent dot, and the plan keeps your choice even when Auto would have chosen differently.

CCR puts the level on the loop. The Setpoint (bar) field becomes editable only when you pick CCR yourself: when Auto put you on the loop, the same slot shows the rig’s value as a read-only line, 1.3 bar · set by Auto. A Diluent row appears below when the rig has more than one diluent option, so you can send one level onto a dilout. See CCR diving.

Travel stops

A level with a time of zero is a travel stop: a depth you pass through to change gas, not a depth you stay at. The Travel stop toggle in the level sheet sets the time to zero, and typing 0 into the time field turns the toggle on. Turning it off sets the time to one minute.

Your gas switch time still applies at a travel stop, so the switch itself costs whatever you set under Gas Switch. On an exported slate a travel stop prints as one switch row rather than as a depth and time pair.

Descent

The planner descends at the Descent rate in your settings. The default is 20 m/min (66 ft/min). Descent time counts toward the runtime and toward gas consumption.

The rate applies to every descending leg, not only the one from the surface to your first level. If a later level is deeper than the one before it, the planner descends to it at the same rate. The descent is modelled as a continuous ramp rather than a jump, so the time you spend on the way down loads your tissues exactly as a real descent would.

That makes the rate a real planning tool, not just a runtime detail. To model a deliberately slow descent, set a low rate: at 2 m/min the planner takes 15 minutes to reach 30 m (100 ft), and that quarter hour on-gasses your tissues the way the real descent would. The row prints the time to reach 30 m (100 ft) under the value, so you can see the effect without doing the arithmetic.

There is no per-level descent rate. One rate governs the whole dive.

One behaviour to understand: the Include travel in level time toggle, in the Behaviour section of the settings. When it is on, the travel time to reach a level is counted inside that level’s entered time rather than added on top. If you enter a level time shorter than the travel required to reach it, the planner warns you and the at-depth stay becomes zero minutes.

Saved plans

The plan list opens when you tap Deco Planner, and it groups repetitive-dive chains together. Each card carries the plan name, an OC or CCR chip, a warning triangle when the cached result had warnings, and a download glyph when the plan came in from a shared link. Under the name a subtitle summarises the dive: the least-rich gas (the one that defines the depth), the gas count, and the gradient factors, or on a rebreather the diluent, the setpoint and the gradient factors.

The card then shows DEPTH, TIME and RUNTIME, and a footer line with the time to surface, the CNS percentage and the level count. A chained plan adds a line reading “Continues from” with the previous dive’s name.

The ⋯ on a card offers Duplicate, Rename and Delete. Deleting a plan other dives chain from warns you that it breaks the chain.

Two buttons sit at the top of the list. Import opens the share sheet so you can scan a QR code or paste a link. Edit Defaults opens the Deco Planner defaults.

Repetitive dives

A repetitive dive starts with the tissue loading the previous dive left you, so it owes more decompression than the same profile dived fresh.

Create one either from Create New Plan → Repetitive Dive, which asks which saved plan you are continuing from, or from Plan Next Dive at the bottom of a plan you already have open, which chains from that plan and asks nothing else. Both then want the Surface Interval between the two dives. It opens at 60 minutes, steps in 15-minute increments, and 15 minutes is the shortest it accepts.

The chain is visible in the plan list, and Chain to Previous Dive in the header menu attaches an existing plan to one. A surface interval you get wrong changes the schedule, so check it before you dive the second plan.

Variants

A variant is a second version of the same plan kept side by side: the same dive at GF 40/70, say, or with a different deco gas. Create Variant in the header menu asks for a label and adds a tab at the top of the editor.

Each variant tab carries an eye toggle that draws that variant’s profile on the graph as a dashed ghost line, so you can see two ascents at once, and a ⋮ with Rename, Set as Default (promotes the variant to be the plan) and Delete. The base tab is labelled Default until you rename it.

Promoting swaps the two tabs whole, names included. A plan called “One bailout” with a variant called “GF 40 70” becomes a plan called GF 40 70 with a variant called One bailout, so the entry in your saved plans list is renamed too. That is what “promotes the variant to be the plan” means: the variant is now the plan, under its own name, and what used to be the plan is kept beside it as a variant. Rename either tab afterwards if you would rather the plan kept its old name. Sharing or exporting while a variant is selected names the variant on the card.

The header menu

The ⋯ in the plan header holds everything that acts on the whole plan.

Item	What it does
Share	Opens the share sheet: QR code, share link, copy link. See Share links
Export	Opens the slate export: PDF, PNG or plain text. See Printing and exporting
Rename	Renames the plan, up to 50 characters
Create Variant	Adds a variant of this plan
Tutorial	Opens the in-app Deco Planner tutorial
Find bottom time	Opens the bottom time finder. Hidden on a rebreather plan, on a bailout view, and on a plan with no gases, because it cannot answer there
Chain to Previous Dive	Continues this plan from an earlier dive’s tissue loading
Delete Plan	Deletes the plan and all its variants, after a confirmation

The whole menu is hidden on a read-only plan.

Share and export a plan

Two different jobs, two different routes.

• Share link and QR code hand over a live plan. The link carries every input, so your buddy opens the dive you planned and their own copy of the engine recomputes it. See Share links and QR codes.
• Slate export produces a fixed card for the water: an A6 PDF, a PNG, or plain text, with two schedules side by side on A5 if you tick Compare. See Printing and exporting a slate.

Behaviour and limits

• The plan is a model. It assumes the gases, depths, rates, and settings you entered are exactly what you dive. Reality (cold, work, current, an off blend) makes you on-gas faster than the model predicts.
• The planner does not know your real cylinder fills or your actual breathing rate on the day. Verify gas analysis and reserves before every dive.
• Repetitive plans carry forward tissue loading from the previous dive across a surface interval, and an imported plan can carry tissue state too. A wrong surface interval changes the schedule.
• Dive Kit does not model a scrubber, thermal stress, or work of breathing beyond the gas density reading.
• Always dive within your training and certification, and follow the most conservative of your computer, your team’s plan, and your judgement.

Related

• Gases in the Deco Planner is the reference for every gas field.
• Deco Planner settings lists every setting and what it moves.
• Reading a deco plan explains every output and warning.
• Contingencies and plan modifiers covers the what-if scenarios.
• CCR diving is the full closed-circuit walkthrough.
• Gradient factors explains GF Low and GF High in depth.
• Gas Blender mixes the gases this plan assumes.