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Calcimator

Dive Profile Planner Calculator

Plan recreational dives using no-decompression limits (NDL). Calculates NDL at depth, safety stop duration, pressure group, and repetitive dive guidance.

Inputs

Results

No-deco limit (min)

45

NDL usage (%)

67

Within NDL?1
Safety stop (min)3
Pressure group (0-25)17
Min surface interval (min)210
Max repetitive depth (m)22
How to Use This Calculator
  1. Enter your planned maximum depth in meters (recreational limit is 40 m).
  2. Set your planned bottom time in minutes.
  3. Indicate if this is a repetitive dive (within 6 hours of the previous dive).
  4. If repetitive, enter your surface interval in minutes to account for residual nitrogen.
  5. Read No-Deco Limit (NDL) in minutes and ensure your planned time stays below 80% of NDL for a safety margin.
  6. Note the Safety Stop duration at 5 m and the Minimum Surface Interval before your next dive.

How the result changes with Planned depth (m)

Planned depth (m)No-deco limit (min)NDL usage (%)
8.721914
185654
2922138
3811273

What each input means

Planned depth (m)
Maximum planned depth in metres. Recreational limit is 40 m.
Planned time (min)
Planned bottom time in minutes.
Repetitive dive?
0 = first dive of the day, 1 = repetitive dive (within 6 hours of previous).
Surface interval (min)
Time since previous dive surfaced (only applies to repetitive dives).

What each result means

No-deco limit (min)
Maximum time at this depth without requiring decompression stops.
NDL usage (%)
Percentage of the NDL consumed by your planned time. Keep below 80% for safety margin.
Within NDL?
1 = your planned time is within the no-decompression limit. 0 = exceeds NDL.
Safety stop (min)
Recommended safety stop duration at 5 metres.
Pressure group (0-25)
Nitrogen loading level after dive (0=A to 25=Z). Lower is better.
Min surface interval (min)
Minimum surface interval before next dive to reach a safe nitrogen level.
Max repetitive depth (m)
Recommended max depth for a repetitive dive after 1 hour surface interval.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Planned depth (m) = 20, Planned time (min) = 30, Repetitive dive? = 0, Surface interval (min) = 60 = 4 input(s) provided
  2. Calculate No-deco limit
    No-deco limit
    45 = 45
  3. Calculate NDL usage
    NDL usage = (plannedTimeMin / adjustedNdl) * 100
    67 = 67
  4. Calculate Within NDL?
    Within NDL?
    1 = 1
  5. Calculate Safety stop
    Safety stop
    3 = 3

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators.

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