The Dive Computer: What it does and why you should have one.

If you’re just discovering the joys of scuba diving, chances are that you’re thinking about the activity itself, not high-tech diving tools.

But a lot can happen underwater, and these tools keep you safe from decompression sickness (DCS) and other problems by tracking a variety of factors during the dive and alerting you of potentially dangerous conditions.

Because it provides all of the information a diver needs, it takes off some of the pressure to make sure your calculations are precise. Human error is a very real factor, even among experts.

Therefore, a dive computer gives you more of an opportunity for spontaneity during the dive itself, making it far more fun.

A dive computer consolidates three separate pieces of diving equipment—a dive table, a dive watch, and a depth gauge—allowing you to possess more with less.

It is a wonderful tool and an excellent companion for your diving journeys. As you read through this article, think of yourself and your potential dive computer as friends with a common goal: a continuing experience of safe, fantastic dives.

Treat your dive computer well and it, as an effective supplement to your human brainpower, will help you reach that end in more ways than you can imagine. Continue below to see what else a dive computer can offer you.

The Beginning Diver


Maybe you’ve already gone on a few dives, or maybe you’re completely new to the activity.

Either way, you’re likely brimming with the novel excitement of surviving underwater without gills and thirsting (pun intended) for more dives.

Diving is incredibly fun, and its complex and often challenging nature keep people intrigued.

Involving mathematical formulas, tables, and intricate equipment, diving is a time-consuming but ultimately highly rewarding pursuit.

It engages the body through physical demand and the intellect through constant calculations, and it is a wonderful outlet for hardworking individuals who are willing to put the time and effort into learning the technical aspects of a new skill.

So congratulations—you are involved in an activity that’s been well loved for decades. Now you face the learning process: the science, the equipment, and—the best part—the practice.

“Practice makes perfect!” may be old news by now, but it’s true.

The one thing that puts a damper on diving practice in particular is that diving done wrong can result in dire circumstances.

As noted before, miscalculations are possible even for the most experienced divers, but they are especially prevalent in beginners. Making mistakes is an important and inevitable part of learning, but mistakes that involve risk can discourage people from learning the skill at all.

This is where the dive computer comes in. The dive computer provides data on diving conditions during the actual dive, and they adjust data as it changes so it can always be relevant to the diver (see next section for further details).

Constant adjustment can give a significant amount of protection to divers who miscalculate at the surface. None of this is to say that beginning divers should replace surface calculations with computer readings: rather, they should use a diving computer in addition to all other planning procedures.

Doing so adds a layer of safety to diving, and beginning divers can be a little more comfortable making mistakes.

As stated above, making mistakes aids and quickens the learning process as long as divers are willing to learn from them—and the dangerous consequences of continued poor diving techniques will likely be motivation enough.

Many dive computers can also transfer data gathered during the dive to a computer, allowing you to look at it in detail (see next section). This gets you even more familiar with the mechanics of diving and enables you to gain skill more quickly.

A dive computer is therefore incredibly valuable to beginning divers, encouraging them to engage in underwater exploration in safe ways. Read on to learn more.

The Dive Computer

The dive computer is a pretty intricate device, but it isn’t unfathomable. Unlike dive tables, computers provide the time of your dive and how deep you are underwater during the actual dive.

They give you the information you need in order to rise safely to the surface (which is arguably the most important part of the dive).

They keep your diving experiences safe, flexible, and fun. This is especially important for the beginner, who has less experience with the necessary calculations and, as a result, less confidence than a seasoned diver in making the necessary calculations.

Even with a dive computer, it is important for the beginning diver to competently calculate target depths, dive times, and ascension rates.

However, a dive computer leaves a little more room for error since it checks and alters your data as needed underwater.

This makes it excellent for the beginning diver, allowing you to learn more quickly from past mistakes and making the process of becoming a seasoned diver an easier and safer one. It also gives you a little more leeway during your dive so you can alter your pre-plans within reason.

This allows you to change a standard square dive into a more complex multi-level dive if conditions allow. With all this information and the epithet “Better safe than sorry,” in tow, it quickly becomes clear that having one of the best dive computers for beginners has infinite upsides and not really very many downsides.

As long as you’re using your dive computer correctly (more about this can be found below), you’re setting yourself up for a ton of great diving experiences by investing in a good dive computer.

What Does A Dive Computer Do?

These are the qualities that every modern dive computer does (and should!) possess.

  • Current depth of dive – This function keeps track of how far you are underwater during your dive.
  • Maximum depth of dive – Even on the ascent, knowing the deepest point of the dive allows the diver to determine important factors—namely, how much stop time is needed. The dive computer records the maximum depth of your dive, keeping it available to you for reference.
  • Time of dive – Your dive computer will monitor how long you are underwater. In many cases (see “Additional Functions” list below), it will also function as a watch and provide the general time—customizable depending on where you are in the world, of course.
  • Ascent rate – During diving, it is important to choose an appropriate ascent rate and ensure you don’t go too slowly or too quickly. A dive computer keeps track of this and warns you if and when your ascent is problematic so you have time to fix it.
  • No stop time – When ascending from deep, long dives, the diver must stop accordingly for decompression checks. No Stop dives—dives in which no stops are necessary—are possible depending on the duration and depth of a dive. What this function does is tell you how much longer your dive can be a no stop dive. After that time runs out, it will be necessary for the diver to perform periodic decompression checks on the way up.
  • Emergency decompression alert – Emergency decompression becomes necessary when the diver goes over his time limit (no-decompression limit). It involves a longer stop at 15 feet below, then waiting at least a few hours before diving again. A dive computer lets you know when emergency decompression is necessary, and it will also tell you what to do based on how far you went over the time limit.
  • Previous dives – Computers in general are smart and hold a lot of information. Dive computers keep track of your previous dives, which helps you in planning future dives. It can also be extremely helpful if you have had a diving accident and want to avoid one in the future. Since the computer records everything, it can be easier to determine what went wrong. From there, you can rectify the mistake and move on.

These are the above-and-beyond qualities that many effective dive computers have. Depending on your budget and your specific diving intentions, some may be additionally beneficial to you.

What Are The Additional Functions Of A Dive Computer?

  • Compass – Knowing where you’re going is good in any situation, especially if you are a beginner in the activity that requires you to navigate. It’s easy to think of underwater traveling as vertical, but water currents can cause you to drift. Having a compass will very much decrease the likelihood of your getting lost.
  • Thermometer – Water temperature greatly influences the dive. You’ll have to wear a thicker wetsuit for colder water. A temperature is also great to have during a dive because water gets colder as it gets deeper, so the temperature won’t be the same as it is at the surface. This can help you plan your dive, and it also helps you stay safe.
  • Air supply information – Humans don’t have gills yet, so running out of air is out of the question. Some dive computers keep information about your air supply for you to keep an eye on during your dive. At the very least, air supply information keeps your mind at rest. It can also give you time to prepare if anticipating a problem.
  • Flexible decompression models – self-adjusting decompression models provide a wealth of relevant information to the diver. Conditions change while underwater, sometimes resulting in an adjustment of your pre-dive calculations and/or a shift in the overall dive plan. The dive computer tracks them to keep its information updated and useful to the diver.
  • Connects to computer – The best dive computers allow you to download your diving data to your computer, making a dive profile. Having records to look back on will allow you to evaluate your dives more deeply and gain a better understanding of everything that makes a dive successful. It may not help you when you’re underwater, but it definitely helps for future dive planning.
  • Games – Nip boredom in the bud by playing a game during a decompression stop. Games keep you from getting antsy underwater, and there’s no danger of getting distracted and losing track of the time—your dive computer will keep you on track. This certainly isn’t a necessary feature, but it’s a very nice one.

Dive Computer Safety Tips

As with all devices, the dive computer works incredibly well when it is used wisely. Dive computers for beginners are especially helpful, since they enable divers to learn the ropes more quickly. On the other hand, it can get in the way of your diving pursuits if used improperly—sometimes even to the level of exposing you to unnecessary dangers.To avoid making this mistake, you should fully educate yourself on the dive computer you use. Also note that dive computers are not a replacement for adequate pre-dive planning.A dive computer is an asset, keeping you aware of conditions in the dive as they are occurring. It should not ever impedeyour planning and calculation process above water. Read on for more safety tips.

Abide by provided boundaries.

Respect your dive computer’s input—it’s more than an opinion! Don’t dive deeper or stay at the bottom of your descent for a longer period than it recommends. If you’re supposed to wait for it to give you the green light, wait for it to give you the green light. Remember, you’re investing in a specialized piece of equipment. For best results, you’ll need to use it for its intended purpose and work with it, not against it. Everybody gets tempted to jump the gun, particularly when they get excited.It’s completely normal—just keep it in check so you don’t put your safety at risk. Just bear in mind that trust is the cornerstone of any successful relationship.

Use backup.

On the off chance that your dive computer malfunctions, you will need a backup plan. If you were at least a few minutes within the no-decompression limits when the computer started malfunctioning, you can ascend (at the recommended rate) to the surface.A quick safety stop just below the surface is recommended. If you weren’t within the no-decompression limits, you will have to get a little more creative with your backup. This can come in the form of extra equipment—a spare dive computer or, cheaper, a spare dive timer and depth gauge. If you don’t want the extra expenditures, find a diving buddy and establish a buddy system. Make sure you have figured out your backup before diving, since you’ll be out of luck if your computer stops working outside the decompression limits and you don’t have backup.

Use your computer consistently.

Every dive computer model is different, so you will not receive the same benefits from borrowing your dive buddy’s computer after leaving yours at home. Present dives influence future dives! Depending on the overall depth and duration of your dive (as well as other factors), you will need to wait a certain amount of time to go on another dive, and usually you can’t safely dive more than a few times a day since that can induce nitrogen narcosis, or too much nitrogen intake. If you dive using a different computer than your own, your computer will be unable to track those dives and give you accurate information about your limitations for future diving endeavors.

Don’t push the limit.

Always leave yourself some wiggle room in anticipation of unexpected circumstances. This isn’t to say that the computer is steering you wrong or claiming you can do more than you actually can.But things can go wrong. If something does go wrong, you don’t it to happen when you’ve been 50 feet below water for 29 minutes and the computer puts your limit at 30. A good tip to avoid this is to decrease your dive time or your maximum depth (or both) from the computer’s given limit.

Keep an eye on battery level.

There’s no magic number here. Batteries differ in longevity, so do your research and see how long your battery lasts. But don’t stop there—use your dive computer and keep track of how long it usually lasts for you. Depending on your computer model, this will differ. And never go diving with a dive computer that is at low battery. It’s risky, and it diminishes the computer’s benefit to you. Charging batteries is no one’s favorite thing to do, which is apparent in general society when people’s cell phones die on them at the worst possible times. But your cell phone isn’t keeping you alive (however some people agree), and your dive computer is. Keep it charged, and keep yourself safe.


Look into causes of DCS.

This may sound a little off topic at first, but the fact is, many different factors can place a person at risk for decompression sickness—and not all of them can be picked up by the computer. Exercising 12 hours or sooner before a dive can put you at risk for DCS, as can dehydration. Be aware of your physical condition before a dive and eliminate risk factors. If you drank a vodka martini a few hours ago, even the best dive computer for beginners cannot help you with that.

Use common sense.

This is very basic but also very important. Diving is complex and unpredictable, and no matter how much you planned before a dive, you are eventually going to run into unexpected circumstances. You will need a good head on your shoulders to be able to navigate these surprises. Good judgment is integral to successful diving, which requires both planning and clarity of mind. In this regard, diving isn’t very different from other world activities. If it’s something you wouldn’t do at sea level, it’s probably something you also shouldn’t do underwater. Dive computers plus a basic knowledge of how to use them make a killer combination underwater.It’s even better if you’re a beginner, since you’ll have a larger learning curve and a safe and secure environment to explore it in.After all, miscalculations are not as much of a problem when you have a dive computer correcting aberrations during the dive, so you will be free to learn and make mistakes—as long as you continue to plan each diving trip.Since dive computers hold onto their data, you’ll be able to analyze each dive later on—giving you the opportunity to learn more quickly from your experience.And if something does go wrong, you’ll be better off with a dive computer so you can discover exactly what happened—and avoid it in the future.Dive computers offer a wealth of information to beginning divers, and—better—they keep beginning divers very safe during the learning process.Knowing the basics is half the battle (although diving is so fun that it’s hardly a battle), so congratulations! Your journey toward a safe, fulfilling dive avocation is well underway.Now head to the next section for tips on selecting a good dive computer. There’s only one step after that—the diving itself.

Finding The Right Dive Computer

Writer Edna Buchanan once said, “Friends are the family you choose.”This perspective is insightful when it comes to friends, but it also provides benefits when extrapolated to other areas. This article began with the proposal to consider your dive computer your friend, and here this idea comes into play with a little more depth. Don’t stop at making your dive computer your friend—make your dive computer your best friend. Find the model that is best suited to your diving needs and preferences. Get something that helps you actualize your greatest diving goals, a quality product that you’ll be able to use for years to come. As a general note, keep your budget in mind. You will always want something that functions well, so it’s a good to avoid the cheapest things. On the other hand, dive computers with fancy add-ons may be less feasible for you. Know your limits and choose wisely.

Air vs. air 2.0 (nitrox)

Nitrox is the scientific name for enriched air, and getting a dive computer that works with nitrox costs a little more than getting one that works with plain air.It’s a good investment since dive computers that calculate nitrox are also able to calculate air—but dive computers that calculate air can only calculate air.The only reason to go with air capacity in a dive computer is if you never plan on using nitrox in the future… and since these computers last years, you should be very sure before making such a decision.

Wrist vs. console

First off, take fashion out of the equation.You’re a diver and will therefore look cool no matter which one you choose.The wrist model resembles a large watch (think 80’s cell phones for scale), and the console model attaches to your diving equipment.The wrist model is a classic, non-fussy choice that will blend in with your street clothes should you forget to take it off after diving.On the other hand, it’s much easier to forget since it’s not attached to your equipment.The console model has the added plus of easy access, but it uses more battery power. Each has its benefits, and it’s really up to you to choose which model you prefer.

How Does A Dive Computer Work?

Fun fact: all dive computers (over a hundred different models) use one of seven different algorithms. Algorithms measure dive depth, gas mixtures, and other factors, creating a mathematical formula from them.Liberal algorithms offer longer dives but with an added risk of DCS, while conservative algorithms air on the side of caution and offer a lower risk of DCS but at the expense of potential longer dives.You will need to consider your age and health and determine which risk factors for DCS you have.If you’re very fit and don’t have many risk factors, you can probably go with a liberal algorithm.If are older and/or have at least several significant risk factors, you should definitely choose a conservative algorithm.This should be considered carefully, so ensure that your self-evaluation of your health is comprehensive and accurate.

Air integration

This is a handy function that measures your breathing rate and calculates how long you can stay underwater at that current rate.By keeping you in the loop regarding your air supply, air integration will also keep you in a calm and knowing state during your dive.For people with general anxiety, this is a godsend—and for people who experience panic attacks, it is a must. Nobody plans panic attacks, and hyperventilating under water can get dangerous—especially if you have no way to keep track of all the extra air you’re using up by doing so.That said, air integration is good even if you are just a bit of a worrier—if you’re constantly thinking about how much air you have left, you will have no time left to enjoy the dive.

PC transfer capabilities

If you want maximal learning capacities from your dive computer, you should absolutely get one that can transfer diving data to your computer.This allows you to access all information tracked at any point during your dive. Most dive computers offer downloading abilities nowadays, and it’s no wonder why: many people use their computers every day and store loads of information on them.The data in a dive computer becomes infinitely more accessible when it can be transferred to your personal computer. While this obviously isn’t a necessary feature of dive computers, it is an important one that significantly enhances your diving experience.For the best diving experiences and the most opportunity for growth, choose a dive computer with PC transfer capabilities.

How Do You Choose A Dive Computer?

Choosing a dive computer isn’t an easy task, but as long as you’re specific about what you want from one, narrowing the list of possibilities won’t take too long.The information provided in this article will help you make an educated choice. That said, there is no such thing as doing too much research, so if you’re in doubt over a model, keep looking for information about it.

Read reviews. Scour any fine print you can find. Go back to general functionality and look further into basic dive computer qualities. You’ll be able to find what you need.

With a dive computer in hand and an abundance of diving knowledge in your head, you have a fruitful diving avocation ahead.

Diving offers the joy of constant mental and physical stimulation, not to mention the fact that you’ll be seeing a variety of locations in a new perspective. Make mistakes, learn from them, and don’t forget to have fun!

  • February 4, 2016
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