MOD & END Calculator

Two related calculators for gas-mix depth planning. Maximum Operating Depth caps your O₂ exposure; Equivalent Narcotic Depth tells you how "thick" the gas feels at depth.

Maximum Operating Depth

Deepest you can breathe this mix before PPO₂ exceeds the safety limit.

O₂ fraction (%)

Max PPO₂ (bar)

Water

Result

Maximum Operating Depth

— m

Mix at this depth: — PPO₂. Beyond this depth, oxygen toxicity risk rises sharply.

Equivalent Narcotic Depth

For trimix. Tells you the depth at which air would feel equally narcotic.

Depth (m)

O₂ (%)

He (%)

O₂ narcotic potency

Water

Result

Equivalent Narcotic Depth

— m

At — m on this mix, narcotic load matches air at the END above. Targets: keep END at or below 30 m for routine tech, 40 m max.