Diving used to be a thrilling, but inexact, science. Based on how deep you were going, you would calculate how many decompression stops you need to make to get the nitrogen out of your system on the way up. A dive computer takes those calculations out of your hands and lets science help you get even further in diving.
The best way to do this is to pair your dive computer’s features with your style or mode of diving.
What is a Dive Computer?
A dive computer is a device worn on your wrist or as a console attached to your diving gear. Because it is constantly calculating your dive time and depth, you don’t need to panic at how slowly you go down (accumulating nitrogen) or how quickly you go up (releasing nitrogen). It adjusts how deep you can go and schedules your decompression stops on the way up.
That being said, as you look at different types of diving conditions or the type of diving experience you hope to have, you should consider different dive computer features as you make your purchase (or rental decisions).
How Do You Choose Your Dive Computer?
There are many modes of diving, but let’s look at two basic categories: entry-level or recreational, and technical.
Choosing an entry-level or recreational dive computer
If you are new to the diving world or you mostly want it for vacations and recreation, you need a dive computer that is straight to the point and easy to use. That means something with a large screen, large numbers and letters, and the most crucial calculations.
- Has an independent system. An independent dive computer is not linked to your air supply and does not give you extra statistics or gauges to watch.
- Can calculate for Nitrox. Your air supply could be either regular or a popular alternative, Nitrox. Because the nitrogen build-up in your body is different depending on your air supply, your dive computer should calculate for both.
- Shows current depth. Even if you choose to stay longer at a certain depth, your computer should recalculate your maximum depth and decompression needs.
- Shows maximum depth. Your dive computer should recalculate your decompression stops based on how long you spend here.
- Has decompression schedule alarms. You will always know when–and how long to–stop for decompression on the way up. Choose an alarm that is either noisy or bright, or both; your health depends on it. (Learn more about the importance of setting alarms while diving.)
Other ideal features:
- Water-activation, so your computer activates automatically
- A backlight, for dark or nighttime dives
Choosing a technical dive computer
A technical dive computer is more adaptable to multiple types of dives. It is usually smaller, with more calculations and varied displays.
- Shows current depth
- Shows maximum depth
- Has decompression schedule alarms
- Keeps dive logs
Is usually an integrated system. A technical dive computer is capable of more calculations than an entry-level one. It can be connected to the air supply and regulation, so you can even monitor how much air you still have and how to manage it.
Can calculate for multiple kinds of air supply. Depending on your kind of dive, you will be using different or multiple mixes of gas, especially if it is a long-term dive. Your technical dive computer allows you to regulate your air supply and sometimes even switch between them.
Has a compass / navigation system. This depends on your kind of dive. If it is an exploration dive with a changing route, you might want to easily find your way back to the dive boat or point, for example.
Exceptions or Alternatives
Free-diving dive computers
If you are a free-diver, your needs are a little bit different. Free-diving dive computers are designed to help you train in holding your breath, and to log and record your dive capacity. What should you look for, then?
- Independent system. Your dive computer should be compact, probably wrist-mounted, and of course not dependent on extra apparatus such as your air supply and regulator.
- Stopwatch. Whether you are in training or already an experienced diver, this should help you keep your diving and surface level intervals consistent.
- Depth monitor. This should help you train for reaching certain depths within specific time limits. This monitors and develops your dive capacity.
- Dive log. Through the log, you can review how you did in the day’s free-diving, and how you can develop it in the next round.
Bottom-timers work for experienced divers who are more comfortable calculating their own decompression stops. The most basic calculate depth and how long you spend at that depth. The more advanced versions allow you to set your desired ascent speed and decompression alarms. The principle is the same, but you retain control of the calculations.
ScubaPro Bottom Timer
Finding the Best Dive Computer
If you’ve found this guide incredibly useful – and we hope you have – and you have yet to purchase a dive computer or are ready to upgrade, we highly recommend you check out our guide to buying a dive computer.