Interactive Nitrox Dive Planner — calculates MOD, EAD, oxygen partial pressure, NDL, and CNS exposure for enriched air mixes.

Recreational · Enriched Air

Nitrox Dive Planner

Working depth, oxygen exposure, and no-decompression limits for any EAN mix between 21% and 40% O₂.

i

TL;DR

Drag the sliders. The tool reports MOD (depth ceiling), EAD (nitrogen-loading depth), PpO₂ at depth, plus your share of the no-deco limit and NOAA single-dive CNS clock for the selected mix.

Plan

Gas mix

O₂ fraction 32%
PpO₂ limit 1.4 bar

Dive parameters

Target depth 30 m
Dive time 30 min
All parameters within safe limits.
MOD 33 m — max operating depth 3 m margin
EAD 24 m — equivalent air depth N₂ load as if on air at 24 m
PpO₂ at depth 1.28 bar — partial pressure Limit 1.4 bar

CNS oxygen clock

—%

Limit at PpO₂ 1.40 bar: 150 min

No-decompression limit

—%

NDL at EAD 25 m: 29 min

Dive profile

Reference — this mix at common depths

Depth PpO₂ EAD NDL CNS rate Status
PADI/DSAT 2009 · Ch. 1.IV · p. 13 PADI/DSAT 2009 · Ch. 4.III · p. 59 NOAA Diving Manual · 4th ed. · CNS O₂ Limits US Navy Diving Manual Rev 7 · Ch. 3
Educational use only. This tool is not a substitute for certified instruction, supervised training, or a verified dive computer / desktop deco software. Always plan dives within the limits of your training and certification, and consult an active instructor or qualified mentor before applying these concepts in-water.
Assumptions & method

Pressure model. Sea-level barometric pressure (1.013 bar). Ambient pressure P = depth/10 + 1 in bar. No altitude correction in v1 — flag if you're diving above ~300 m.

MOD. MOD = 10 × (PpO₂_max / FO₂ − 1). Floored to whole metres. Values 1.0–1.6 bar in 0.1 bar steps; working dives 1.4 bar, deco/short-exposure 1.6 bar, conservative 1.2 bar.

EAD. EAD = ((1 − FO₂) × P_amb / 0.79) × 10 − 10. The depth at which air would impose the same nitrogen partial pressure as your nitrox mix at the target depth.

NDL. Looked up at EAD against the PADI Recreational Dive Planner. EAD is rounded up to the next deeper bin (conservative — matches RDP convention). EAD beyond 40 m → outside recreational scope, deco required.

CNS clock. NOAA single-exposure limits at PpO₂ 1.6→45 min, 1.5→120, 1.4→150, 1.3→180, 1.2→210, 1.1→240, 1.0→300. PpO₂ at depth is rounded up to the next 0.1 bar bin for limit lookup. Single-dive only — does not track 24-hour cumulative exposure or repetitive dives.

Profile chart. Square profile: 10% of dive time descending, 15% ascending, balance at depth. Real dives are multilevel — this is illustrative.

What this tool does NOT cover (yet): repetitive diving, surface intervals, residual nitrogen, altitude correction, ascent-rate violations, decompression schedules, OTU/whole-body O₂ tracking, gradient-factor models. For those, use a verified dive computer or desktop planner.