EADDEquivalent Air Density Depth
Equivalent Air Density Depth of breathing gas at selected depth.
Dense gas is harder to breathe and raises the risk of CO₂ build‑up. EADD tells you at which depth air would be as dense as your mix is at the planned depth.
How it works
EADD = (ρ mix ÷ ρ air) × (depth + 10) − 10
- ρ gas density at STP: 1.429 g/L × FO₂ + 1.250 g/L × FN₂ + 0.179 g/L × FHe
- ρ air 1.288 g/L
Example
- Gas
- Tx 21/10 (1.180 g/L)
- Depth
- 40 m
- EADD
- 1.180 ÷ 1.288 × 50 − 10 = 35.8 m
How it works
EADD = (ρ mix ÷ ρ air) × (depth + 32.8) − 32.8
- ρ gas density at STP: 1.429 g/L × FO₂ + 1.250 g/L × FN₂ + 0.179 g/L × FHe
- ρ air 1.288 g/L
Example
- Gas
- Tx 21/10 (1.180 g/L)
- Depth
- 120 ft
- EADD
- 1.180 ÷ 1.288 × 152.8 − 32.8 ≈ 107 ft
Take it to the dive site
The same calculator works offline in the Deep Tools app, together with the dive planner, dive log and blender.
