⚠️ Important: This NDL estimator assumes air (21% oxygen) only. It is not valid for Nitrox / Enriched Air dives.

How to Use This NDL Time Estimator

This tool gives a conservative estimate of the maximum no-decompression bottom time for a single recreational dive at a planned depth. It is for educational planning only.

You will need:

• Your planned average depth (not maximum depth)
• The unit you prefer (metres or feet)
• A conservatism level (recommended: Conservative)

Steps:

1. Enter your planned average depth
2. Select metres or feet
3. Choose a conservatism level (Normal, Conservative, or Very Conservative)
4. Click Estimate NDL

The calculator will show your estimated no-decompression limit (NDL) in minutes.

Safety note: This tool assumes air (21% oxygen) only. It does not apply to Nitrox / Enriched Air. It does not replace dive tables, a dive computer, or professional training. Always follow your dive computer and agency standards.

NDL Planning Tips for Safer Dives

No-decompression limits are not targets — they are upper safety boundaries. Plan your dives with margin and keep these points in mind:

📉 Plan well inside the limit

Always plan to finish your dive before you reach the NDL. Treat the displayed time as a ceiling, not a goal.

🔁 Repetitive dives reduce your NDL

Your available no-decompression time will be shorter on subsequent dives. Use longer surface intervals and follow your dive computer closely.

❄️ Add margin in demanding conditions

Cold, current, poor visibility, stress, and heavy workload all increase decompression stress. In these situations, plan shallower and shorter dives.

💧 Stay hydrated and rested

Dehydration and fatigue can increase physiological stress and reduce safety margins. Drink water and get enough rest between dives.

🖥️ Always follow your dive computer

Your dive computer or tables always override any online estimator. If your computer says ascend, ascend.

Good dive planning is not about pushing limits — it’s about ending every dive comfortably, with time and gas to spare.

No-Decompression Limit (NDL) Time Estimator

This tool gives a simple, conservative estimate of maximum no-stop time for a single recreational dive. It is for educational planning only.

Safety note: This does not replace dive tables, a dive computer, or professional training. Always follow your dive computer and agency standards.

How to Use This NDL Estimator

• Enter your planned average depth (not maximum depth).
• Choose metres or feet.
• Select a conservatism level (recommended: Conservative).
• Click Estimate NDL.

Always plan shorter than the limit and follow your dive computer.

Inputs

Planned average depth

metres (m) feet (ft)

Use average depth from your dive computer or plan.

Conservatism level

Normal Conservative Very Conservative

Multiplies the estimated limit to add safety margin.

Estimate NDL Reset

Simple Safety Tips

• Plan dives to be shorter and shallower than the limit.
• Add extra margin when cold, tired, in current, or doing repetitive dives.
• Use longer surface intervals on multi-dive days.
• Stay hydrated and well rested.

More Scuba Diving Tools

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• Dive Gas Time Planner (Tank Duration Calculator) – https://africandiveadventures.com/dive-gas-time-planner-tank-duration-calculator/
• NDL Time Estimator (No-Decompression Limit) – https://africandiveadventures.com/no-decompression-limit-ndl-time-estimator/
• Rock Bottom Gas Calculator (Minimum Gas) – https://africandiveadventures.com/rock-bottom-gas-calculator-minimum-gas-for-scuba-diving/
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