Can You Fill a CO2 Tank With Compressed Air (Answered)

Is your paintball gun out of gas? Do you have a CO2 tank, but have no CO2 to refill it? 

Refilling a CO2 tank with compressed air is certainly possible. But there are some dangers in it if the refilling process is not done properly. The tank’s integrity must be ensured before refilling. The PSI rating must also be considered. It is always better to underfill than to overfill.  

That’s just the gist of it. We have a detailed article regarding cross-refilling right here. 

Can You Fill A Paintball CO2 Tank With Compressed Air

Yes, refilling a co2 tank with compressed air is possible? But it is easier said than done. 

Tanks are specially made for their pre-purposed fuel. So refilling a co2 tank with compressed air has its own set of challenges. But it can be done.

To fill a co2 tank with any other fuel you will absolutely need an adapter. The adapter will make the co2 tank compatible with compressed air. 

Filling Compressed Air in a CO2 Tank: 2 Concerns

As we already said, tanks are specially designed for specific fuels. So cross-filling can be dangerous. There are two main things that worry us regarding filling a CO2 tank with compressed air. They are:

Concern 1. Shooting Issue

Compressed air generally offers better accuracy. But that is only true when you are using compressed air in a tank made for compressed air. Compressed air in a CO2 tank is not guaranteed to offer better accuracy. 

Compressed air in a CO2 tank may slow your gun’s fire rate. Sometimes it may even stall the shooting completely. Reduced accuracy is another thing you may feel. These might completely ruin the paintball game for you.

Concern 2. Tank Explosion

The previous issue was bad for your paintball experience, but this issue is actually dangerous. If the filling process is not done meticulously, there is a chance of the tank exploding 

While filling the tank, the pressure of the tank and the compressed air must be considered. Incompatibility can be very dangerous.

How Do You Fill A CO2 Tank?

So how to fill a co2 paintball tank at home? The process is a little complicated. Just follow these steps: 

Step 1: Checking Integrity

Begin by inspecting the tank. Check to be sure whether the tank has a hydro-testing number. The hydro-testing number is usually painted on the body of each tank. 

If you do an initial test on a smaller unit, no hydro test is required. But if the container was tested within the previous five years, it is safe to use. 

However, if the tank lacks a number of hydro testing, then you must do a hydro test. The test must be done for your own safety before you use the tank. 

Step 2: Understanding the Rating of Container PSI

The PSI rating of the tank is marked on the exterior of the tank. Or it may be marked on the bottom side of the container. 

The PSI rating is written as “3AL1800” or “E3000.” The rating always starts with a letter and ends with a lengthy serial number.

The letter present in the serial number denotes the regulatory authority’s standards to which the cylinder conforms. The number, in contrast, is referred to as the primary rating of PSI. 

Let’s try to understand the PSI rating of the above examples. The first tank’s serial number means it has a PSI rating of 1800. While the other tank’s PSI rating is 3000. 

So this is how you identify the PSI of a tank. You must be sure about the PSI rating of the container.

You should never attempt to fill the tank over its maximum capacity. Whatever gas you’re filling, it’s always best to underfill the tank than overfill it. 

This procedure also applies to the CO2 tank. But if you use 100% dry and oil-free air, you may fill up to the maximum capacity. 

However, if you are unsure whether the air is dry and oil-free, it is best to underfill. Overfilling can be very dangerous. 

Step 3: Using the Appropriate Fill Adapter 

The CO2 tanks and compressed air tanks have separate settings. This will assist you to avoid any risk if you unintentionally put the wrong sort of gas in the cylinder. 

But an adapter will help you with this. The adapter lets you attach the CO2 container as easily as you would a compressed air container.

Here are some of the best adapters you can try-

The danger level of compressed air tanks varies depending on their principal function. CGA-320 or CGA 347 threading is commonly seen on CO2 tanks. 

Before purchasing any adaptors, you must be aware of the threading on your compressor. Along with the threading on your CO2 bottle. 

Knowing both of their threadings will assist you in determining the best fit for your tank. You will need a full seal to perform the refilling properly.

Step 4: Emptying the Tank Completely

Before you can add anything to your tank, you must fully empty it. Be absolutely sure that the tank is completely empty.  

When it comes time to connect your adapter to the tank, connect it with the hose fitting. Connect it while the compressor is not connected. 

There is a valve that lets any residual air leave. It even allows you to open the tank. Before you begin filling the tank again, be sure to close the valve.

Step 5: Using a High-Pressure Air Compressor

To refill the CO2 tank, you will absolutely want a high-pressure air compressor. A CO2 container won’t be filled with a low-pressure pump. Even a hand pump that only goes up to 150 PSI will not suffice. 

The compressor must produce the correct PSI for your tank. This is an absolutely crucial requirement.

Some specific compressors will not provide you with private scuba-fill statistics. However, it is useful for certain people who utilize alternative compressed air.

There is a built-in bleed-off valve as well as a PSI pressure gauge, these should come in handy.

Sometimes the compressor may become too hot or the filling flashes the maximum amount of 4500 PSI. In that case, the compressor will shut off automatically. 

Keep in mind that you cannot set the auto-stop to a certain PSI level for other sizes. As a result, you must exercise extreme caution and keep a close eye on it. 

Remember, do not overfill the tank. When the tank is full or almost full, turn off the compressor. 

Unbolt the container from the compressor’s hose. Do it after opening the bleed valve for a second or two to empty up the lines and avoid any buildup. 

And with that, you are done!

Difference Between CO2 and Compressed Air

Differences between CO2 and compressed air are essential to know for any user. So naturally, the two will change the performance of your airgun in some ways.

Here are some 2 aspects where you can feel the difference.

Gun Chilling

Gun chilling or tank chilling is a phenomenon that only happens with CO2 fuel. Airguns are able to shoot due to liquid CO2 expanding. 

The expansion of CO2 is because of the CO2 cooling down. When constantly shooting, the CO2 constantly cools down. The decrease in temperature goes down further and further with every shot. 

The cooling down of the CO2 tank, and the whole gun, affects the performance of the gun. The accuracy may heavily drop. The firing rate will also fall.

As we said, this problem only happens with CO2. While using compressed air, you will have no such problem.


CO2 tanks are more readily available. Almost everyone is familiar with using guns fueled by CO2. 

Services for CO2 tanks are much more available. More places offer CO2 refills than compressed air refills. Sometimes service shops even offer free refills for CO2. 

So while using CO2-fueled guns, you will get more readily available services and help.


CO2 tanks themselves are much cheaper than compressed air tanks. This is why CO2 tanks are much more common. 

Refilling a tank with CO2 costs around $5. Sometimes service shops do it for free. Refilling compressed air, on the other hand, is much more pricey.


How many paintballs can a co2 tank shoot?

The number of paintballs a co2 tank can shoot depends on the volume of the tank. But other factors, such as temperature, can affect the number of shots. Generally, you can expect to get 700 shots from a 14 oz co2 tank.

Is compressed air better than CO2 for paintball?

Compressed air is not necessarily better than co2. But compressed air is much more consistent and offers high accuracy and range. Compressed air also does not suffer from tank chilling, which co2 is prone to. But compressed air is much more pricey in the long term. 

Does Home Depot refill CO2 tanks?

CO2 tanks cannot be refilled in Home Depot. But the stores do sell the necessary products needed for refilling a co2 tank. You can use these products to refill the tank yourself. But if you want someplace that refills co2 tanks, Home Depot is not the destination.


Now we know the answer to Can you fill a co2 tank with compressed air? You can, but the process is a little lengthy. 

Follow our guide and you will not face any trouble. Good Luck!

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