Computer Buying Guide Written by: Alex Jones Created: 01/18/2018 Updated: 02/15/2026

What is a Dive Computer?

In simple terms, a dive computer is a device used by a scuba diver to measure the time and depth of a dive based on a pre-programmed algorithm. In reality, today a dive computer is as important a piece of diving equipment as your regulator. It constantly calculates and displays a safe dive profile and ascent rate for you so you can avoid decompression sickness.

Why Should You Buy A Dive Computer:

Again simply put, a Dive Computer extends your bottom time. In contrast to dive tables that only calculate “square diving profiles" based on your MAX DEPTH and MAX TIME after your dive. Your dive computer continuously calculates based on your ACTUAL DEPTH and ACTUAL TIME during your dive.

Their ability to automatically measure your depths and time means they are able to warn you that you're approaching your max NDL or Bottom-time, warn you of an excessive Ascent Rate and even help time your Safety Stop. Dive computers also allow you to more accurately calculate your dive profile for Repetitive Dives during your surface interval.

Because dive computer's continually “re-calculate” based on changes in the depth and time of a divers profile, you benefit by being able to safely remain underwater for longer periods of time and by being given more chance for spontaneity during your dives.

Basic Features:

Dive computers today display four main pieces of information all divers should measure throughout their dive:

1. Current depth of the dive.
2. Maximum depth achieved during the dive.
3. NDL or “No Stop Time” (the remaining allotted time for a particular depth without requiring a decompression stop during ascent).
4. Overall dive time (the time measured from the start of the descent to the beginning of the direct ascent to the surface).

Other features to consider: NITROX has now become a standard feature. The ability to download dive information via Bluetooth to a PC or phone. Air Integrated capability to measure Tank pressures. Dive log history, backlights for night dives, and audible/visual alarms.

Air Integrated Dive Computers:

Many dive computers today are being produced with a feature called Air Integration (AI). An air integrated computer tells the diver the pressure in their tank and eliminates the need for a separate pressure gauge.

The computer determines the diver’s rate of breathing and how much longer their tank will last. By measuring both the no-decompression limit and remaining air pressure, the computer determines which factor is the limiting one, allowing for the maximum safe dive time possible.

Wrist or Console Mount:

Modern dive computers come in two basic setups:

Wrist computers: Stand-alone units connected via a watch band or bungee. Available in standard "puck" sizes or smaller watch styles for everyday wear. They help eliminate hoses from your regulator setup and some offer wireless AI transmitters.

Console computers: Mounted in your SPG console, usually replacing the depth gauge. If air integrated, they replace both the depth and pressure gauges in a normal console setup.

Advantages Of Using A Scuba Computer

A dive computer simplifies your dive planning. Here are five good reasons to use one:

1. Avoid the "max depth penalty" associated with manual dive tables.
2. Receive current and accurate real-time data.
3. Store and download dive logs via Bluetooth.
4. Avoid human calculation errors common with dive tables.
5. Access advanced features like Nitrox, Ascent indicators, and Safety Stop timers.