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How to Measure PC Fan Size

The size of the fan you want will usually be determined by the size of the fan fitting position in your computer case it is easy to measure pc fan size.

All fan sizes on our site are shown measured with one of the four sides of the fan, not the distance between the fan screw holes! Our most popular fan size is 120mm, followed by 80mm.

How to Measure PC Fan Size?

There are always built-in fans with PC cases, which can give adequate cooling to the basic system.

However, if the fans are not working adequately, or are not enough to keep the system in check, then you need to get extra PC fans.

There are so many CPU coolers that customers can choose from. These CPU coolers are available on Amazon, and they come in different shapes, sizes, and features.

Noctua NH-D15 is a CPU cooler, which comes with a six-year warranty. The cooler performs very well and is quiet in most cases. However, before considering this cooler, the customer should measure whether it will be good for their PC or not.

Another CPU cooler is Cooler Master Hyper 212 RGB, which performs efficiently. It can be easily installed and has quiet fans. It comes with RGB lighting, which is not very impressive.

There are several things to consider when buying a PC fan or measure pc fan size.


The first thing you need to see is whether you want a 3 pin or 4 pins fan. If you want a 3 pin fan, then know that it has wires for power, ground, and tach.

Tach delivers information to the motherboard and the software, as RPM does. Those fans who have the 4th pin will allow users Pulse Width Modulation Control.

This permits the motherboard, or the fan control software you have installed, to adjust the fan’s speed.


The speed of a fan is measured in Revolutions Per Minute. It tells the user how many a fan makes a complete rotation, in one minute. If the RPM is high, then the fan’s speed is high as well.

Most speedy fans are loud and irritating for users, which is why users would want to control RPM.

Size of the Fan

In most modern cases, the size of a fan is 120mm. However, if users want more choices, then they can find several CPU fans on Amazon for different sizes and prices. Other fan sizes include 80mm, 92mm, and 200mm.

If someone has a large fan, then it is more likely to push more air than the smaller fans, at the same RPM.

Large fans spin slowly, as compared to smaller ones, but they will provide the PC with the same amount of air. With larger fans, the noise level is low, as compared to small fans.

Before buying a fan for the CPU, it is best to check their compatibility with the computer case.


Fan noise can be very irritating, and they usually become loud when the system overheats and they have to work more.

When buying a PC fan, make sure to check the decibel level of the fan, which you can find in technical specifications.


CFM stands for cubic feet/minute. This metric tells the user how much their fan is capable of moving air.

This specification is important because it will tell how well a fan will perform.

Power Consumption

If you don’t want your electricity bills to increase, then check how much power a fan is going to use, before you buy it.

Amps measure the power that a fan consumes. If a fan has a power of .12A and a voltage of 12v


Lastly, how a fan look is important because most people would want their product to stand out from the crowd.

There are many color schemes in which a fan is available, and there are manufacturers who attach LEDs to fans as well. When they attach LEDs to fans, this makes them more appealing.

Measuring Fan Size

There is no definite way of measuring fan size. The size of a fan that a user needs to buy can be determined by looking at the PC case, and the size of the fitting position.

There are different sizes of fans on every online website selling PC fans and they are usually measured by a fan’s four sides.

Some websites measure the screw hole spacing and fan sizes. For example, if the screw hole spacing is 32mm, then the fan size is 40mm. If the screw hole spacing is 83mm, then the fan size is 92mm.

The most common depth of a PC fan size is 25mm, which is 1 inch. However, if the fan is small, then it can have a shallow depth of 15mm or 10mm.

Most of the fans come in 25mm size unless the brand has stated otherwise. Before ordering a fan, the customer should always ask its size from the seller, if it is not stated in the ad. Knowing the size of the fan would tell the user if it would be appropriate for their PC or not.

When you are buying a CPU fan or cooler online, you will see different measurements given by the manufacturer with a measured pc fan size.

For example, a Cooler Master Hyper 212 has dimensions 120×79.6×158.8mm. The weight of the cooler is 1.54 pounds and its decibel is also mentioned in the specification; 8-30.

Keeping these measurements in mind, a customer can decide whether they want this cooler or not. More helpful guide: here

How to find out what fan your PC has?

There are multiple ways through which you can find out what fan your PC is using such as opening up your CPU and seeing it for yourself.

That being said, there are several ways to check the performance of your fan and this article will show you how.

Without further ado, let us get into it.

  1. Download and install SpeedFan
  2. Launch the application
  3. All information related to your computer fan will be displayed on the main program window.
  4. Compare your fan’s RPM with the normal RPM range listed in the manual or specifications sheet for it
  5. Click the “charts” tab and select “fan speeds” from the drop-down menu.
  6. Next, place a checkmark next to the label corresponding to your CPU fan to begin generating a chart of the variation in the fan’s speed.

Now you can view your fan’s performance in the form of a chart.

Where is the CPU fan located?

The CPU fan is located at the top of the processor. The CPU fan is responsible for blowing hot air off from the processor, to keep it cool.

Do people need a CPU fan?

Everyone needs a CPU fan because it helps in the cooling down process of a processor.

However, a customer doesn’t have to always buy another one, if their current processor isn’t overheating or making too much noise.

How do CPU fans work?

A CPU fan is attached to a computer case, so it can provide active cooling to it. Fans draw cooler air into the case from the outside and expel the warm air from the inside. This helps the heat to cool down the components.

How big is a 120 mm fan?

80mm fan size – 71.5mm between screw holes. Fan size of 92mm – 82.5mm between screw holes.

120mm fan size – 105mm between screw holes. Fan size of 140mm – 124.5mm between screw holes.

Are all PC fans the same size?

In the case of modern PCs, the 120mm case is the most popular size for fans, but you will find many sizes such as 80mm, 92mm, 140mm, 200mm, and more.

The size of the fan is closely related to the airflow, in which large fans will move at the same RPM to move the smallest air.

What size case fans do I need?

Sizing and growing

The first concern on your to-do list should be the size of the fan. Most modern cases use 80, 120, or 140 mm fans, but some cases and CPU coolers use everything from 40 to 200 mm.

The size of your case should be listed manually or online. Otherwise, you can measure from the mounting hole to the mounting hole.

Can I plug 4 pins into 3 pins?

Two of the pins provide power to the fan, the third provides an RPM plus to the motherboard for speed reading. The fourth pin is for PWM speed control.

If you plug a 4 pin static into a 3 pin socket, the fan speed will be controlled by voltage and it will still work.


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