US Navy Dive Planner

Enter depth and bottom time to get the no-stop limit, your repetitive group and any decompression stops from the US Navy air tables. Works in feet or meters.

Results update as you type.

Quick examples

Load a full example, then change any value.

Depth unit

Maximum depth (ft)

The deepest point of the dive. It is rounded up to the next table depth.

Bottom time (min)

From leaving the surface to leaving the bottom, descent included.

No-stop limit

Within limits

At 60 fsw the no-stop limit is 63 minutes. Your 40-minute dive needs no stops and leaves you in group H.

Table and schedule: 60 fsw, Table 9-7
No-stop limit: 63 min
Repetitive group: H

Was this calculator useful?

This page is for education and reference. The US Navy tables are written for Navy divers with surface-supplied gear, recompression chambers and trained supervisors. Recreational dives stay within no-decompression limits and 130 ft (40 m). Plan real dives with your training agency's tables and a dive computer.

About the US Navy air tables

The US Navy Diving Manual, Revision 7 (2016), introduced the current air tables. Change A (2018) left them as they were. Navy divers use them with surface-supplied gear and recompression chambers at hand.

The planner does the lookup you would do in the printed tables. It finds the row for your depth and time, then reads the no-stop limit, any decompression stops and your repetitive group. For a repetitive dive it first adds the residual nitrogen time.

With your numbers

Enter valid values to see the calculation worked through with your numbers.

Formula

Depth and time: round up to the next table value

drow = first table depth ≥ d

Meters to feet

dft = (dm) ÷ (0.3048)

Repetitive dive

ESDT = t + RNT

Where

d, t: maximum depth and bottom time
RNT: residual nitrogen time from Table 9-8, for your group at the end of the surface interval and the depth of the repetitive dive
ESDT: equivalent single dive time, used to read Table 9-7 or 9-9 at the repetitive dive depth
Meters are converted as a length and then rounded up to the next table depth, which stays on the safe side

How it's calculated

Depth and bottom time are rounded up to the next values in the table (paragraph 9-6.1).
Within the no-stop limit the group comes from Table 9-7; past it the schedule, stops and group come from Table 9-9.
A surface interval under 10 minutes counts as one dive. Past the last interval in a group's row the next dive is not a repetitive dive.
Source: US Navy Diving Manual, Revision 7 Change A, Volume 2, Chapter 9, Tables 9-7, 9-8 and 9-9.

Good to know

Bottom time starts when you leave the surface, so descent time is part of it.
If the dive went deeper or longer than planned, use the schedule for the real depth and time.
Doing the deepest dive first and the shallowest last gives the most bottom time for the least decompression. The manual allows other orders.
RNT exception rule: you may also plan a repetitive dive as one dive with the bottom times added together at the deeper depth, and use whichever plan needs less decompression.

How to use the US Navy dive planner

1
Single Dive: pick feet or meters and enter your maximum depth and bottom time. Both are rounded up to the next values in the table.
2
Repetitive Dive: pick the group letter from your last dive and the time you spent on the surface, then enter the next dive.
3
Read the no-stop limit and your group. If stops appear, the planner shows them on air and with oxygen at 30 and 20 fsw.

What the results mean

The no-stop limit is the longest bottom time at that depth that still allows a direct ascent at 30 ft/min without decompression stops.

The repetitive group, from A to Z, tracks the nitrogen left after a dive. It drops during the surface interval and sets the residual nitrogen time for the next dive.

The equivalent single dive time is your bottom time plus the residual nitrogen time. The next dive is planned as if it lasted that long.

← Back to the US Navy tables