Scuba Diving Calculations

Tools for calculating Dalton's Triangle and U.S. Navy No-Decompression Limits

Dalton's Triangle Calculator

Enter any 2 of the 3 values below to calculate the third value and related gas pressures.

Results:

Depth: 0 ft
O₂ Percentage: 0%
Ambient Pressure: 0 ATA
Partial Pressure O₂: 0 ATA
Partial Pressure N₂: 0 ATA

About Dalton's Law

Dalton's Law states that the total pressure exerted by a mixture of gases equals the sum of the partial pressures of the individual gases.

In diving, this is crucial for calculating:

  • Oxygen toxicity risk (pO₂ > 1.4 ATA is considered the recreational limit)
  • Nitrogen narcosis risk (pN₂ > 3.94 ATA can cause significant impairment)

U.S. Navy No-Decompression Limits

Calculate maximum bottom time without decompression stops based on U.S. Navy dive tables.

Interactive Dive Tables

Click on elements in the tables below to plan your dive:

  1. Click on a depth row in Table 1
  2. Click on a bottom time to see your pressure group
  3. For repetitive dives, click on your pressure group row in Table 2
  4. Click on a surface interval to see your new pressure group
  5. Your adjusted no-decompression limits will be highlighted in Table 3

Calculation Results:

Selected Depth: -- ft
No-Decompression Limit: -- minutes
Pressure Group: --

Nitrox (EANx) Settings

Maximum Operating Depth (MOD): -- ft
Table Mode: Air (21% O₂)

Table 1: No-Decompression Limits and Repetitive Group Designation

Depth (ft) No-Deco Limit (min) Pressure Group Designation
A B C D E F G H I J K

Table 2: Surface Interval Credit Table

Group at Start of Surface Interval Group at End of Surface Interval
A B C D E F G H I J K

Table 3: Adjusted No-Decompression Limits (Minutes)

Depth (ft) Pressure Group Designation
A B C D E F G H I J K

About No-Decompression Limits

No-decompression limits (NDLs) are the maximum amount of time you can stay at a given depth without requiring decompression stops during ascent.

These limits are based on the U.S. Navy dive tables and are designed to prevent decompression sickness.

For repetitive dives, you must account for residual nitrogen from previous dives by:

  1. Determining your pressure group from the first dive
  2. Finding your new pressure group after surface interval
  3. Adding residual nitrogen time to your actual bottom time

Always plan your dive conservatively and consider using a dive computer for real-time monitoring.