---
title: "Every number the planner gives you"
description: "What each readout on the Review step means, and just as importantly what it does not mean."
---

> Documentation Index
> Fetch the complete documentation index at: https://docs.divelogic.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Every number the planner gives you

import { PlanSummaryDemo } from "@/components/react/PlanSummaryDemo";
import { trimixDeco } from "@/demo/plans";

Every readout on the Review step, in the order the step presents them. Each one
is what one model predicts for the dive you described, not a measurement.

## The six readouts

| Readout | What it is | What it is not |
|---|---|---|
| **Max Depth** | The deepest point of the dive, to a tenth of a metre. | Not the deepest level you asked for, if the descent overshoots it. |
| **Runtime** | The whole dive: leaving the surface to breaking it again, rounded to the minute. | Not just your bottom time, and not the decompression alone. |
| **TTS** | Time to surface: from the end of the last bottom segment to the surface. | Not a countdown you can read at any point in the dive; it is the figure for this plan, computed from its bottom time. |
| **First Stop** | The depth of the deepest mandatory stop. | Not shown at all on a no-stop dive. |
| **O₂ CNS** | The central-nervous-system oxygen clock for the dive, as a percentage of the single-exposure limit. The bar behind it fills toward 100 %. | Not a probability of a seizure, and not additive across days in the way OTU is. |
| **OTU** | Oxygen tolerance units: whole-body pulmonary oxygen exposure for the dive. | Not a depth limit or a time limit. It matters over repeated days more than within one dive. |

Both oxygen figures are running totals to the end of the dive, decompression
included. See [Oxygen exposure](/theory/oxygen-exposure).

### The limits the CNS clock is scaled against

100 % is the NOAA single-exposure limit for the oxygen partial pressure you are
breathing. The clock interpolates between these:

| ppO₂ | Limit | ppO₂ | Limit |
|---|---|---|---|
| 0.60 bar | 720 min | 1.20 bar | 210 min |
| 0.70 bar | 570 min | 1.30 bar | 180 min |
| 0.80 bar | 450 min | 1.40 bar | 150 min |
| 0.90 bar | 360 min | 1.50 bar | 120 min |
| 1.00 bar | 300 min | 1.60 bar | 45 min |
| 1.10 bar | 240 min | | |

Nothing accumulates at or below 0.50 bar. The allowance falls from 120 minutes
to 45 between 1.50 and 1.60 bar, which is why 1.60 bar is treated as a
decompression ceiling rather than a working limit.

## The schedule

The table comes at three densities: **basic**, the calm everyday row; **slate**,
the stripped set you would copy onto a wet slate; and **advanced**, the full
instrument set, scrolled sideways in its frame.

Each column heading carries its unit on a second line — **Depth** over
*metres*, **Time** over *minutes* — so the values themselves are bare numerals.

| Column | What it is |
|---|---|
| **Phase** | What the line is: Descent, Level, Stop, Ascent, Gas switch or Setpoint switch. A gas, diluent or setpoint switch is its own row rather than folded into the segment around it, in Advanced only. Not shown on the slate, which drops every row but Level and Stop. |
| **Depth** | The depth of this line of the schedule. The first line reads *Surface* (Basic and Advanced only — the slate drops the implicit surface line along with descents, ascents and switches). |
| **Runtime** | Elapsed time from leaving the surface to the end of this line. This is the number you compare your bottom timer against. |
| **Time** | How long this line itself lasts. On a stop, this is the stop time. |
| **Gas** | What you are breathing on this line, and on which circuit: `CC 10/70`, `OC 50%`. On a bailout schedule the same list carries both, and the prefix is what tells them apart. |
| **ppO₂** | The oxygen partial pressure you are breathing on this line, in bar. Basic and Advanced only; the slate shows the same figure as **Setpoint** instead (see below). |
| **ppN₂, ppHe, fO₂, fN₂, fHe, Density, END** | The inspired breathing-gas figures behind that ppO₂, one column each. Advanced only. |
| **Ceiling** | The decompression ceiling: the shallowest depth the model permits at that moment. Advanced only. |
| **CNS, OTU** | The running oxygen-exposure totals at that line. Advanced only. |
| **Setpoint / Waypoint / Turn** | Slate only, one or the other depending on the line's circuit: **Setpoint** on a closed-circuit line, **Waypoint / Turn** (remaining pressure over turn pressure, flagged **Below turn** as a caution) on an open-circuit one. Both appear on a bailout schedule. |

Your depth stays at or below the ceiling for the whole ascent; where the two
meet, you are at a stop. A gas switch and a setpoint change are their own line
on Advanced, placed at the exact depth the change happens. See
[Reviewing a plan](/planning/reviewing).

## Gas used

Each gas in the plan gets its own accounting on the Gas Consumption tab.

| Readout | What it is |
|---|---|
| **Starting Pressure** | What the cylinder was filled to. |
| **Used Pressure** | What the dive takes out of it. |
| **End Pressure** | What is left at the surface. Shown in a warning tone when it is low, and in an error tone when the dive needs more gas than you carry. |
| **Remaining** | The same figure as a percentage of the fill, and again as litres. |
| **Starting / Used / End Litres** | The same accounting in free-gas litres at the surface, shown when the plan knows the cylinder's size. |

A negative **End Pressure** is not clamped at zero: the dive as planned needs
gas you have not brought. Pressure figures need both a tank size and a working
pressure on the gas; without them the volume is still given in litres. See
[Gas consumption](/gases/consumption).

## Turn pressure, level by level

One card per level, below the consumption cards, worked in the pressure of your
back gas.

| Readout | What it is |
|---|---|
| **Start pressure** | The back gas's fill pressure. |
| **Runtime** | Elapsed time at the end of this level. |
| **Leaving at** | What is left in the back gas as you leave the level. |
| **To next switch** | The gas you need to reach the next gas switch, or the surface if there is none, covering every stop and ascent on the way. |
| **Reserve** | A third of the starting pressure, held back. |
| **Turn pressure** | *To next switch* plus *Reserve*. The pressure at which this level has to end. |

A card is flagged **Below turn** when the pressure you leave the level with is
under its turn pressure, and **Supply exceeded** when the plan needs more than
you carry. These figures never change the schedule. They appear only when the
back gas has both a size and a fill pressure and the level actually happened in
the profile.

## The profile

The dive drawn against time: depth downward, runtime across, each segment
coloured by the gas you are breathing on it, with the ceiling drawn alongside
and gas switches marked where they happen. Full screen shows the same numbers
larger.

## Tissue saturation

On a Bühlmann plan, the Tissue Saturation tab shows all sixteen compartments
through the dive, one row each, fastest at the top, labelled **C1** to **C16**
with its half-time. Colour is how full the compartment is against the limit the
model draws for it, and the trace above the map is the leading compartment's
gradient factor. Thalmann and the hybrids have nothing of this shape to show.
See [Tissue compartments](/theory/tissues).

## Hybrid Analysis and GF Calibration

**Hybrid Analysis**, on the hybrid models, shows how far the two models
disagreed about the ceiling, which of them was holding you at any moment, and
the alternative schedules the search found: a fastest, a most conservative, and
the balanced one you were given. The risk scores beside them are internal
measures. **None of them is a probability of decompression sickness**, and they
mean nothing compared against another dive's.

**GF Calibration**, on that algorithm, shows the gradient-factor pair DiveLogic
fitted, how closely the fitted schedule tracks the Thalmann one, and how much
shorter or longer the two are. See [GF calibration](/theory/gf-solver).

## Bailout scenarios

On a CCR plan, each scenario is listed with the gases it uses and its time to
surface, and any two can be laid over each other for comparison. A scenario is
marked when its shallowest usable gas is not breathable at the bail depth, in
which case the ascent stays on the loop until it is. Scenarios taking more than
five times the loop plan's runtime are dropped from the list. See
[Bailout planning](/ccr/bailout).

## Read next

- [Reviewing a plan](/planning/reviewing) works through these readouts in order.
- [Units and rounding](/reference/units) says which way each of them rounds.
- [Warnings and errors](/reference/warnings) lists every message that sits beside
  them.

Source: https://docs.divelogic.ai/reference/outputs/index.mdx