Diving tables are a safe, simple, and inexpensive tool for planning a diving profile, but they have several limitations. The most prominent of these is that when planning a diving profile using a diving table, we considered the depth as if we were at the maximum depth for the entire duration of the dive, while in most cases we will stay at the maximum depth for a short time and perform the rest of the dive at shallower depths.

When using a dive table, the bottom time can be calculated according to the maximum depth planned for the next dive. Such a diving profile is called a "square profile". However, in practice, we perform a variable depth profile - also called a "multilevel dive". The dive computer will calculate dive times considering the change in depths in real time, and therefore the bottom times we get when diving with a computer will in most cases be longer than those allowed by the diving table.