Question 1

What is the 'best' nitrox mix for diving?

Accepted Answer

The 'best' nitrox mix is the highest oxygen percentage you can safely breathe at your planned depth without exceeding the recommended partial pressure of oxygen (PPO₂) limit. This maximizes your bottom time by reducing nitrogen absorption while staying within safe oxygen exposure limits. For most recreational diving, this means using a PPO₂ of 1.4 bar as the safety threshold.

Question 2

How is the optimal nitrox mix calculated?

Accepted Answer

The formula is: Optimal O₂% = PPO₂ ÷ (Depth ÷ 10 + 1). For example, at 30 meters with PPO₂ 1.4: O₂% = 1.4 ÷ (30 ÷ 10 + 1) = 1.4 ÷ 4 = 35%. Since standard blends are sold in whole numbers, you'd use EAN36 for this depth. Our calculator uses this formula to instantly show the best mix for any depth between 12 and 40 meters.

Question 3

Why is PPO₂ 1.4 used as the default limit?

Accepted Answer

A PPO₂ of 1.4 bar is considered the conservative safety limit for recreational Nitrox diving. While 1.6 bar is the maximum allowed by many dive agencies for a single dive, 1.4 bar provides an additional margin of safety, especially for longer or repetitive dives. This conservative approach reduces the risk of Central Nervous System (CNS) oxygen toxicity.

Question 4

What is the best nitrox mix for shallow dives (10-20 meters)?

Accepted Answer

For shallow dives between 10-20 meters, higher oxygen mixes are safe and beneficial. At 15 meters, the optimal mix at PPO₂ 1.4 is EAN40 (40% oxygen). At 18 meters, it drops to EAN36. These higher blends significantly extend your bottom time compared to air by reducing nitrogen absorption.

Question 5

Does the best nitrox mix change at different depths?

Accepted Answer

Yes, the optimal oxygen percentage decreases as depth increases. At shallow depths (12-18m), you can safely use high-oxygen blends like EAN36-EAN40. At medium depths (20-30m), the best mix drops to EAN28-EAN36. At deeper recreational depths (32-40m), only lower-oxygen blends like EAN21-EAN28 are safe. This is why it's important to calculate the best mix based on your specific planned depth.

Depth	Best Mix	MOD	EAD
12 meters	EAN40 (40%)	25.0 m	6.7 m	Details
13 meters	EAN40 (40%)	25.0 m	7.5 m	Details
14 meters	EAN40 (40%)	25.0 m	8.2 m	Details
15 meters	EAN40 (40%)	25.0 m	9.0 m	Details
16 meters	EAN40 (40%)	25.0 m	9.7 m	Details
17 meters	EAN40 (40%)	25.0 m	10.5 m	Details
18 meters	EAN40 (40%)	25.0 m	11.3 m	Details
19 meters	EAN40 (40%)	25.0 m	12.0 m	Details
20 meters	EAN40 (40%)	25.0 m	12.8 m	Details
21 meters	EAN40 (40%)	25.0 m	13.5 m	Details
22 meters	EAN40 (40%)	25.0 m	14.3 m	Details
23 meters	EAN40 (40%)	25.0 m	15.1 m	Details
24 meters	EAN40 (40%)	25.0 m	15.8 m	Details
25 meters	EAN40 (40%)	25.0 m	16.6 m	Details
26 meters	EAN38 (38%)	26.8 m	18.3 m	Details
27 meters	EAN37 (37%)	27.8 m	19.5 m	Details
28 meters	EAN36 (36%)	28.9 m	20.8 m	Details
29 meters	EAN35 (35%)	30.0 m	22.1 m	Details
30 meters	EAN35 (35%)	30.0 m	22.9 m	Details
31 meters	EAN34 (34%)	31.2 m	24.3 m	Details
32 meters	EAN33 (33%)	32.4 m	25.6 m	Details
33 meters	EAN32 (32%)	33.8 m	27.0 m	Details
34 meters	EAN31 (31%)	35.2 m	28.4 m	Details
35 meters	EAN31 (31%)	35.2 m	29.3 m	Details
36 meters	EAN30 (30%)	36.7 m	30.8 m	Details
37 meters	EAN29 (29%)	38.3 m	32.2 m	Details
38 meters	EAN29 (29%)	38.3 m	33.1 m	Details
39 meters	EAN28 (28%)	40.0 m	34.7 m	Details
40 meters	EAN27 (27%)	41.9 m	36.2 m	Details

Best Nitrox mix for every depth

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