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Plan safe recreational scuba dive profiles from air supply, depth, and SAC rate. Estimate bottom time, turn pressure, and remaining gas at ascent.
Plan decompression stops for technical scuba diving. Estimate required stop depths and times based on bottom time, depth, and gas mix for safe ascent.
Calculate scuba air usage rate at depth from SAC rate and dive depth. Estimate PSI per minute, cu ft consumed, and remaining dive time from tank pressure.
Multiply oxygen fraction by absolute ambient pressure. Recreational limit is 1.4 ATA during working dives and 1.6 ATA for decompression. Exceeding limits risks central nervous system oxygen toxicity.
ppO2 = (FO2 ÷ 100) × P_absRearrange the ppO2 formula to find the deepest depth where oxygen partial pressure stays at or below your chosen limit. Use 1.4 ATA for bottom gas during recreational dives.
MOD (ft) = ((Max ppO2 ÷ (FO2/100)) − 1) × 33EAD shows the equivalent nitrogen loading depth if breathing air. Lower EAD means extended NDL compared to air at the same actual depth, which is the primary benefit of nitrox.
EAD (ft) = ((1 − FO2/100) ÷ 0.79) × (Depth + 33) − 33Updated: July 2026
32% nitrox at 100 ft yields ppO2 of 1.45 ATA — above the 1.4 working limit. MOD for EAN32 at 1.4 ATA is approximately 111 ft, so plan average depth below 100 ft.
EAN36 at 60 ft gives EAD near 48 ft, extending NDL significantly compared to air. Verify MOD (≈95 ft at 1.4 ATA) before planning deeper excursions.
After analyzing a fill with an oxygen analyzer, enter the measured FO2 to confirm MOD for your planned dive profile matches your certification and dive plan.
Enriched Air Nitrox (EANx) blends contain higher oxygen percentages than standard air, extending no-decompression limits but imposing depth restrictions. Enter oxygen percentage, planned depth, and FO2 limits to calculate Maximum Operating Depth (MOD), Equivalent Air Depth (EAD), and partial pressure of oxygen.