Equivalent Air Depth - Calculations in Metres

Calculations in Metres

The equivalent air depth can be calculated for depths in metres as follows:

EAD = (Depth + 10) × Fraction of N₂ / 0.79 − 10

Working the earlier example, for a nitrox mix containing 64% nitrogen (EAN36) being used at 27 metres, the EAD is:

EAD = (27 + 10) × 0.64 / 0.79 − 10

EAD = 37 × 0.81 − 10

EAD = 30 − 10

EAD = 20 metres

So at 27 metres on this mix, the diver would calculate their decompression requirements as if on air at 20 metres.