Free tools
Free scuba diving calculators
Interactive tools for the theory that trips beginners up — nitrox limits, gas planning and what certification actually costs. Free, instant, no signup.
Nitrox MOD Calculator
Enter your oxygen percentage and PO₂ limit to get your maximum operating depth (MOD) — and the best mix for a target depth.
Maximum Operating Depth (MOD)
33.8 m
111 ft — deeper than this, EAN32 risks oxygen toxicity
Educational estimate using the standard MOD formula. Always analyse your own cylinder, verify the blend on the label, and dive within your training and your computer’s limits. Nitrox requires an Enriched Air certification.
Air-Duration Calculator
Estimate how long your gas will last at depth from your cylinder size, pressure, depth and breathing rate.
Estimated time at depth
≈ 33 min
Using 150 bar of gas at 2.8 ata (50 L/min)
Rough planning estimate assuming a constant depth and breathing rate. Real dives vary — cold, current and stress raise consumption. Always monitor your gauge, turn the dive at your planned pressure, and surface with your reserve.
Certification Cost Calculator
Budget your Open Water certification by region, with materials, gear rental and personal-gear options.
Estimated total
$833–$1127
Typical range — prices vary by shop, season and class size
Ballpark 2026 estimates in USD to help you budget — always confirm exactly what a specific dive shop’s price includes. The certification itself is a one-time cost that never expires.