Dive Tables

Printed tables giving no-decompression limits and repetitive dive calculations for square profiles, the classic tool for planning depth and time.

Dive tables are printed charts that tell you how long you can stay at a given depth without required decompression stops, and how to account for nitrogen carried over between repetitive dives. You enter with your planned maximum depth, read the no-decompression limit, and after the dive use your depth and time to find a pressure group, which combines with your surface interval to adjust the limits of the next dive. Well known examples include the PADI Recreational Dive Planner and the US Navy tables.

Tables assume a square profile, as if you spent the whole dive at maximum depth, which makes them conservative for a typical multilevel dive that spends most of its time shallower. Dive computers replaced tables for most divers precisely because they track your actual profile continuously and credit you for the shallow portions. The underlying decompression models, descended from Haldane and refined by Buhlmann and workshop data, are the same family that computer algorithms use.

Tables still earn their place: they are the backup when a computer floods or dies, the planning check before a dive, and the clearest way to learn the relationship between depth, time, and nitrogen. Most agencies still teach them for exactly that reason. Working a repetitive dive problem on paper once in a while keeps the concepts sharp, even if the computer does the arithmetic on every real dive.