---
title: "Mix at depth"
description: "Reading ppO₂, MOD, density, EAD and END for any mix at one depth, against the same limits the planner checks a plan with."
---

> 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.

# Mix at depth

import { MixAtDepthScreen } from "@/components/react/ToolScreens";

Mix at depth answers *what does this mix do at this depth?* Give it a mix and
a depth and it returns the partial pressure of oxygen, the maximum operating
depth, the gas density and two narcosis depths, each measured against its
limit. It is the first tool in the **Gas** group.

## What you enter

- **Oxygen** (%) and **Helium** (%): the mix. Nitrogen is the remainder.
- **Depth** (m): the depth to read the mix at. Enter 0 m to see the mix at the
  surface.
- **Max ppO₂**: your working oxygen limit, 1.2, 1.4 or 1.6 bar. It sets the
  MOD and the dashed mark on the ppO₂ rail.

## Reading the result

- **ppO₂** (bar): the main figure. Its rail runs to 2.0 bar, with a solid mark
  at the **1.6 limit** and, when your **Max ppO₂** is lower, a dashed mark at
  yours. It turns amber above your limit and red above 1.6 bar.
- **MOD** (m): the deepest depth at which the mix stays within your Max ppO₂,
  rounded down to the whole metre. It turns red when it is shallower than the
  depth you entered.
- **Density** (g/L): dashed mark at the **5.2** advisory, solid mark at the
  **6.2** limit. Amber above 5.2, red above 6.2.
- **EAD** (m): equivalent air depth, counting nitrogen as the only narcotic gas.
  Dashed mark at 30 m; amber above it.
- **END** (m): equivalent narcotic depth, counting oxygen as narcotic as well,
  which gives the deeper and more conservative figure. It carries the same 30 m
  mark but does not change colour; the narcosis caution follows EAD.

The verdict repeats the most serious finding in words. With nothing to report
it reads, for example, *Breathable at 25 m, inside every limit.* At 30 m,
as above, EAN32 is just past the 5.2 g/L density advisory, so the density
figure and the verdict are amber.

## What it leaves out

- **A mix too lean to breathe shallow.** Nothing warns about hypoxia. For a
  bottom mix below 21 % oxygen, read its ppO₂ at 0 m and at your travel depth.
- **Fresh water and altitude.** The figures assume salt water at sea level.
- **Time.** It reads one depth at one moment. Oxygen exposure over time is
  [CNS and OTU](/tools/cns-and-otu); a whole dive is a plan.

## Next

- [Best mix](/tools/best-mix) works the other way round, from depth and limits
  to a mix.
- [Depth limits](/gases/analysing) covers the same checks on a gas in a plan,
  and [Gas density](/theory/gas-density) explains the density limits.

Source: https://docs.divelogic.ai/tools/mix-at-depth/index.mdx