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What Size Shop Vac Do I Need? [4 Categories Explained]

It’s a very confusing matter to choose to buy a shop vac. Deciding whether the shop vac is suitable for my task is very difficult.

What size shop vac do I need? 

The size depends on tank size, horsepower, CFM, and sealed pressure. But the simplest way to figure this out is by knowing why you need it. For example, if you want to maintain a small household, get a small shop vac. If you want to clean an office, grab a medium shop vac. If you’re a professional, buy a large shop vac.

You must still be confused regarding which size to choose. We have discussed some features to clear yourself out. Read along for the details!

What Size Shop Vac Is Suitable For You?

A shop vac is a modern time-saving cleaning tool. You should obviously have one of these in your house or business. 

But to choose a suitable shop vac for you, you should keep a few things in mind. These are-

  • Tank size 
  • CFM 
  • Sealed pressure
  • Horsepower 

Let’s know the categories in detail now. It will surely help you to determine which shop vac you need. 

According To Tank Size 

The size of the tanks are classified as small, medium, and large. The 3 most common ranges of tank size are-

Shop Vac SizeTank Size
Small2-6 gallon
Medium6-14 gallon
Large14-18 gallon

It’s also important to check out what these tanks are used for-

Small Tank 

You might want to clean your room or car or your pet’s hair or sitting water. In that case, a small tank shop vac would be enough for you.

Medium Tank 

You need a medium tank for work such as house renovation. Because that’s when you are intended to clean more dust and dirt.

You might not have that big of a business. For example, in a stall or an office, medium shop vac will work the best.

Large Tank 

If you are engaged in a huge renovation project, a target tank is the best choice. Because it will help you remove all the dust and dirt produced from your work.

A large tank is mostly for professionals. But if you are undergoing lengthy construction such as retiling a bathroom, get this one. 

According To Sealed Pressure

Sealed pressure is also known as suction pressure. It’s a suction rating point for a shop vac. 

Sealed pressure is mostly measured for water removal. For good water removal, you will need good sealed pressure.  

Sealed pressure is typically measured in inches of water. It is rated by how many inches of water a vacuum will lift up. 

There are 3 categories of shop vac according to sealed pressure-

Shop Vac SizeSealed Pressure
Low 50 inches 
Medium 70 inches
High75 inches

You can choose a high sealed pressure shop vac for a good result.

But to accumulate with it, you will need a larger tank. It would be foolish of you if you use a smaller tank with a 75 rated sealed pressure vacuum. 

According To CFM 

CFM is an acronym for cubic feet per minute. It measures the air volume in cubic feet.

In shop vac categories CFM also means the amount of air it can suction. You can get a little confused between CFM and PSI. But PSI stands for something else.

Shop vac with a larger CFM is going to pull larger pieces of debris. Higher the CFM is always best for you.

Sometimes you might buy a shop vac according to horsepower. But it might have a lower CFM. As a result, it will not perform to your expectation. Because of lower CFM, it means lower suction.

The shop vac comes in mostly these range of CFM- 

Shop Vac SizeCFM
Low60-75 CFM
Medium75-150 CFM
HighMore than 150 CFM

Most commonly a 125 CFM is a good product. You can choose a 125 CFM shop vac for small or medium tasks.

But if you are doing a huge cleaning task you should choose a higher CFM shop vac. To accumulate with higher CFM, you will need a larger tank and larger hose. 

According to Horsepower

Horsepower is mainly related to CFM and sealed pressure. To run with a higher CFM, and sealed pressure, you will need a higher horsepower.

You can probably guess the higher the horsepower, the bigger the shop vac. As a result, to accumulate with higher horsepower, you will also need a larger tank.

Here are 3 categories of shop vac according to horsepower-

Shop Vac Size Horsepower
Small1-4.5 horsepower
Medium5-6 horsepower
HighMore than 6 horsepower

You can now easily say the bigger the task is, the bigger the shop vac. 

Which Shop Vac Best For You? 

For maintaining a household cleaning as new construction basement water, buy a small shop vac. This way you will have a small-size tank with low horsepower. But in case you pick a one with higher CFM, you will definitely receive good results. 

If you have a business or office, you may choose a medium shop vac. It will have a medium size of tank, CFM, and horsepower. 

If you are a contractor involved with cleaning, go for a large shop vac. Choose a high CFM and higher horsepower. It will make your work easy.

Here are some best shop vacs in the market we have suggested for you-

Product 1
Product 2

They are of good quality, which is easy to maintain.


Question: Can you use a shop vac without the bag? 

Answer: No, you can’t. Because the fine debris and dust will go through your filter and blowback into your room without it. As a result, it’s mandatory to use your collection bag with a foam sleeve.

Question: Can I use my shop vac for water? 

Answer: You can use your shop vac for water. It’s best if you add a garden hose to your shop vac. It will do the proper work. 

Question: Does a shop vac lose suction with a longer hose? 

Answer:  Hose is an inverse factor to the suction, the longer the hose is the lower the suction will be. It’s because of the available hose space.

Bottom Line 

We hope you are crystal clear about the query what size shop vac do I need.

Try to understand your working essentials before buying a shop vac. Consider buying a quality product that suits your work.

Good luck with buying a shop vac!