Newly certified divers are frequently excited to gain in the water and explore the large world in ~ the surface. Each new environment brings through it new underwater ecosystems, different types of sea creatures, and also even wrecks come explore.

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However, that is regular for the new diver to have many questions once planning their first dives. Among the most regular questions is just how long a scuba tank lasts once diving.

After all, her air resource is your lifeline underwater. Understanding exactly how long you deserve to safely it is in beneath the surface ar is key to gift able to arrangement dives and have confidence. So, precisely how long does a scuba tank last when diving?

While over there isn’t specific answer, start divers ~ above a usual dive will uncover that their scuba tanks carry out approximately 45 to 60 minutes of underwater time while still offering a safe reserve of air. Factors that impact this incorporate maximum depth, breathing rate, lung capacity, and tank size.

Obviously, the is not feasible to state with certainty precisely how long a tank will certainly last because that each diver. This is why checking her air levels throughout dives and communicating effectively with your dive buddy space important.

However, knowledge the components that affect your time underwater will help you learn to better plan dives.


A usual Dive – What provides it critical 45 Minutes

Anyone who has a handful of dives in their logbook knows that each dive is different. For this reason what perform we typical by a “typical dive?” for a usual dive, let’s take into consideration the dives most frequently undertaken by beginners v an open up water certification.

Open water certification way that you can dive up to 60 feet. However, most of your very first dives will be a little shallower, commonly in the range of 30-40 feet.

At this range, you are more likely to acquire the 45 minute underwater mark.

This is because from 30 feet come 60 feet, air consumption increases significantly (we’ll discuss why later).

Your common dive also assumes some information around your equipment. The most typical rental tank supplied is one 80 cubic foot aluminum version. This usually has 3,000 pounds every square customs (PSI) that compressed air.

This air, under problems of a usual open water dive, will enable most divers to hit the 45 minute mark.

Another thing to consider is the water temperature. We’ll assume you diving in heat or reasonably temperate water. While over there are renowned dive spots about the globe, the many frequented ones – particularly for beginners – room in warmer climates.

Finally, let’s make some assumptions about you because individual differences influence air consumption as well.

Let’s to speak you’re a guy that is 5’10” and also 200 pounds or a woman the is 5’4” and also 160 pounds. We’ll also assume you are of typical fitness and engaging in a relaxing dive without strenuous effort.

During this “typical” dive, you’ll spend a few minutes descending come depth.

This will vary a bit depending on how simple or difficult you find it to equalize ~ above the means down. Once at depth, you will spend many of your dive exploring the environment, taking in the sights the coral and marine life.

You will spend up to half an hour in ~ this depth, gradually cruising approximately the reef. Obviously, checking your pressure gauge regular is important throughout this time.


The last ten minute of her time underwater will certainly be scheduled for her ascent. This contains the essential safety protect against at about 15 to 20 feet that will last for 3 to 5 minutes.

A typical diver top top this usual dive will certainly reach the surface after roughly 45 minutes with a for sure reserve of waiting in the tank.

However, what if you room not the typical diver top top a typical dive? stop look at the components that can impact your tank times.

What Factors impact the size of a Dive?

If you aren’t engaging in the “typical” dive, you’ll desire to know the different components that influence how long her scuba tank lasts.

This will aid you much better plan the length of her dive. There room a variety of factors; however, the an easy ones are depth, exertion, breath rate, tank size, and also lung capacity.


Depth is among the easiest components to understand.

Deeper depths result in much more rapid usage of her air supply. Psychic from your training the pressure boosts as friend dive.

The surface has actually a press of one atmosphere, which boosts by one every 33 feet. Thus, an altering a dive native 33 feet (2 atmospheres) to 99 feet (4 atmospheres) doubles the pressure.

This is important because it method that higher pressure is being used to both you and also the air friend breathe, definition even at the same price of breathing, you space consuming much more air from your tank.

Thus, the deeper girlfriend dive, the much more quickly you usage your waiting supply.

This is among the easier determinants to predict because it is fairly stable mathematically. If friend know exactly how long a tank lasts because that you in ~ 30 feet, you have the right to predict how long it will certainly last at various depths.


This is straightforward to understand, but harder to predict.

Essentially, girlfriend burn through air more quickly as soon as you exert yourself more underwater. This is why scuba divers tend to move rather slowly and also deliberately underwater. That decreases breathing, providing more time in ~ depth.

There are different things that will certainly require much more exertion.

For example, if you room diving in current, you will certainly exert yourself more. However, divers can enhance your air it is provided in basic by practicing an ext fluid movements and improving your buoyancy.

Breathing Rate

The simplest thing a diver have the right to do to increase their time underwater is to practice their breathing. Slow, complete breaths will fill the lungs (improving efficiency) and allow for every carbon dioxide to it is in exhaled (increasing the time prior to the mind sends a signal to inhale again).

Temperature also plays a function here. During colder dives, we normally breathe an ext rapidly as our body looks for to produce more heat come compensate because that the heat we shed to the water.


Tank Size

Aside from depth, tank dimension is possibly the easiest element to calculate. If you usage a tank with an ext air, friend will have the ability to stay underwater longer. For this reason why not just use a huge tank top top every dive?

As friend learned in her training, time in ~ depth is minimal not simply by the air supply but likewise by nitrogen absorption (which additionally varies through depth). Thus, the typical tank will be perfect for most start divers.

Lung capacity & general Biology

Your biology additionally plays critical role.

If friend are reasonably large, your lungs will most likely be huge as well. This way you will use more air through each breath than a smaller diver.

Fitness levels play a duty here also as someone in poor fitness will certainly breathe more while who in good fitness will breathe less.

In fact, improving your fitness and practicing her breathing are two ways to help compensate if you have a larger lung capacity.

Do pair Tanks twin Your Dive Time?

You may have seen civilization dive with twin tanks and also wondered if castle are more efficient through air usage.

The basic answer is yes.

There room two factors for this. First, pair tanks can be collection up to just hold an ext air because that a dive by having an increased complete tank size. This means more time underwater.

Additionally, there is a functional advantage to the design.

Twin tanks have actually two linked but independent regulators. Let’s say one diver bring away two solitary tanks the 3,000 PSI for two afternoon dives.

Another diver takes pair tanks, each with 3,000 PSI every cylinder. Once the an initial diver gets back to the boat after their initial dive, he has actually air left in the tank the is discarded when he switches tanks.

Meanwhile, the twin tank diver doesn’t should switch tanks and also doesn’t discard this air. It have the right to be supplied on his 2nd dive.

Twin tanks might be an efficient solution if you find that you usage your air an ext frequently than a common diver.

It is likewise a an excellent option because that deeper dives together a security feature.


Final Thoughts

Ultimately, many divers will discover that a typical rental tank of 3,000 PSI will last 45 come 60 minutes during a dive in ~ the depth that 30 feet.

With greater fitness and lower breath rates, time underwater will certainly increase.

Meanwhile, much more exertion and diving at greater depth will reason your time underwater to decrease.

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Divers who uncover they use their air supply quicker than the norm can practice lowering breathing rates, improve their fitness, opt for a larger tank, or think about a pair tank setup.