Will A 3-gallon Air Compressor Run An Impact Wrench?

An impact wrench requires a minimum volume of air compressor to function. But the question is how to understand the exact volume of air compressor to run an impact wrench. Will a 3-gallon air compressor run an impact wrench? Let us understand the capacity and functioning of impact wrenches and air compressors to know what we exactly need.

The scientific fact is that a 3-gallon air compressor is too weak to run an impact wrench. The more the air pressure in an air compressor, the more the power. 3-gallon is too less to produce enough power to run an impact wrench. You need at least a 10-gallon air compressor to run an impact wrench without delay. However, a 20-gallon air compressor is considered the best in this case.

What is an impact wrench?

An impact wrench is a tool designed to produce high torque output with minimal effort by the user. Compressed air is most often a common power source for impact wrenches. They also produce high rotational torque, which normal drills cannot deliver.

All You Need To Know About Impact Wrenches

What is an air compressor?

An air compressor is a pneumatic machine that converts the power of pressurized or compressed air into potential energy using an electric motor or diesel. An air compressor forces a large amount of air into the storage tank and increases the pressure till it reaches the upper limit. We can use the kinetic energy of the compressed air in the tank for several purposes, like running an impact wrench. When the pressure in the tank decreases, the air compressor switches on once again to refill the tank.

How do air compressors help impact wrenches?

As already explained, air compressors turn the power of compressed air into potential energy to help tools like impact wrenches function. However, the pressure of the air compressor should match the requirements of the impact wrench. You must assess whether the impact wrench will match a certain air compressor and the minimum power it can exert. The air compressor’s working pressure should be higher than the impact wrench’s minimum pressure. If the air compressor’s working pressure and efficiency are weaker than the impact wrench requirements, it won’t work smoothly due to insufficient pressure. The constant delay will frustrate you.

How much air pressure do impact wrenches need?

The air pressure (PSI) and the flow of air (CFM) measure the power of an air compressor. The more the air pressure, the more efficiently the impact wrench functions. 

CFM stands for Cubic Feet per Minute and denotes the mass of air flowing in a minute. 

PSI stands for Pounds per Square Inch and is the unit for air pressure. 

Therefore, the question arises, how much air pressure is needed for an impact wrench? The answer depends on the size of the impact wrench in the first place. The larger the impact wrench, the more powerful it is; thus, the more air pressure it needs to function. 

· 1/4-inch impact wrench:-

A 1/4th-inch impact wrench is the smallest size and does not need great air pressure. An air compressor with 1 – 1.5 CFM can easily run a 1/4th-inch impact wrench. 

· 3/8-inch impact wrench:-

A 3/8-inch impact wrench needs more power than a 1/4th-inch one. You need roughly double the amount of power here. Therefore, the air compressor must have at least a power of 3- 3.5 CFM to run this size of an impact wrench. 

· 1/2-inch impact wrench:-

The 1/2-inch impact wrench is the most common type of impact wrench available. An air compressor with 3.5 to 5 CFM would be perfect for running a 1/2-inch impact wrench. 

· 1-inch impact wrench:-

A 1-inch impact wrench is large, powerful, and only used at construction sites. These need a high amount of air pressure to function. Air compressors with 9 to 10 CFM can run a 1-inch impact wrench. 

Read more: Should I Get 3/8 Or 1/2 Impact Wrench?

Impact wrench size chart based on CFM and PSI:

Size of Impact WrenchAir ConsumptionPressure
1/4-inch Impact Wrench1 – 1.5 CFM90 PSI
3/8-inch Impact Wrench3- 3.5 CFM90 PSI
1/2-Inch Impact Wrench3.5 – 5CFM90-100 PSI
1-inch Impact Wrench9 to 10 CFM90-125PSI
Impact wrench size chart

Tank size of air compressors

While air pressure largely decides whether the air compressor can run a specific size of an impact range, considering the tank size is also important. Air compressors come in different sizes according to the tank capacity. The tank size is measured in gallons and determines the amount of air the tank can hold to exert the air pressure. The larger the tank size of the air compressor, the more air it can hold and the more pressure it can generate. 

Will a 3-gallon air compressor run an impact wrench?

Even though impact wrenches are not used for continuous stretches of time, unlike sandblasters, a 3-gallon tank size of an air compressor sounds too weak for the job. Air compressors above 6 gallons can still work with constant delays. A minimum tank capacity of 10 gallons can make your impact wrench function smoothly. However, a 20-gallon one is the best choice you can make for professional work.

A 3-gallon air compressor is the most popular and inexpensive one available. These are the beginner’s range of air compressors, available on a very low budget. But, they are extremely weak in terms of air pressure. It won’t be able to store as much air needed to produce considerable air pressure and work reliably. A 3-gallon air compressor can hardly even produce 1 CFM of air pressure. Therefore, you can understand how inefficient it would be to run even the smallest impact wrenches. Investing in such an inefficient tank capacity wouldn’t be wise if you work with impact wrenches.

Thus, if the question in your mind is, will a 3-gallon air compressor run an impact wrench, the answer is no. It is a very basic one that you have and cannot help you run a powerful tool like an impact wrench. 

Choose the right capacity

A 6-gallon air compressor can help the job get done with frequent delays. This is the minimum size that you can still choose for impact wrenches. However, be prepared to wait every couple of minutes to refill the tank. Even a 6-gallon air compressor will run out of air every few minutes and need to refill before you start again. People who occasionally use the impact wrench for their homes shouldn’t mind the delay. It does not seem a big deal to them. But, for professional work, even 6-gallon proves to be practically useless. For them, 10 gallons to 20 gallons is the recommended size. Construction sites dealing with high-power impact wrenches of 1-inch need air compressors of nearly 30 gallons tank size to exert the required air pressure.

What work does a 3-gallon air compressor do? 

A 3-gallon air compressor can perform light jobs like inflating tires. Such jobs do not require continuous use or high power. Since a 3-gallon air compressor has very low CFM and PSI, and the small tank needs constant refilling, it has very few uses like:-

  • Inflating tires for bicycles.
  • Inflating sports items like balls.
  • Operating nail guns. 
  • Operating light-duty air blowers.

FAQ about 3-gallon air compressors

How long does it take for 3-gallon air compressors to fill up?

A 3-gallon air compressor usually takes 1 to 3 minutes to fill to maximum capacity. However, it takes nearly 45 seconds to a minute to refill the tank after it runs out of air. It depends on the model and the CFM rating. 

What are the CFM and PSI ratings for 3-gallon air compressors?

A 3-gallon air compressor usually has a 0.5 to 1 CFM rating and 90 to 150 PSI rating. 

Is it worth buying a 3-gallon air compressor?

If you are buying an air compressor for running an impact wrench, then the answer is no. However, if you want a portable, basic air compressor to fill tires and use light air tools, a 3-gallon size is sufficient. It can be a handy tool for performing basic jobs. But if you want to go for something more, you need a powerful air compressor rather than this one. It cannot help you grind, cut or repair in the garage. 3-gallons models are best-suited for DIY tasks.

What factors should you check while purchasing the best air compressor for impact wrenches?

  1. Endurance– The shelf life of any product is important. When you invest in something, you obviously want it to run for a long time. 
  2. Tank size– As explained above, always go for models with a 10-gallon tank size or above for smooth functioning and professional use of impact wrenches. 
  3. Size of impact wrench- Consider the size of your impact wrench and choose the required CFM and PSI per the chart.


The short answer to the most asked question, will a 3-gallon air compressor run an impact wrench, is no. It’s no point investing in such a beginner’s level air compressor if you are professionally dealing with impact wrenches. It would prove inefficient for the job and frustrate you with the endless waiting time spent refilling the tank. It’s recommended to go for a 10 to 20-gallon air compressor with 5-8 CFM power to perform the job smoothly. 

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