How to Measure CPU Fan Size: A Complete Guide

When building or upgrading a PC, one crucial component to consider is the CPU fan. The fan plays a significant role in keeping your system cool and ensuring optimal performance. But before you purchase a new CPU fan, you need to know the right size to ensure compatibility with your CPU cooler and case. In this guide, we will walk you through how to measure your CPU fan size accurately, step by step, to help you make the best choice for your setup.

Table of Contents

Why is CPU Fan Size Important?

Choosing the correct CPU fan size is critical for a couple of reasons. First, the fan’s size determines its compatibility with your CPU cooler and the space within your PC case. Additionally, a fan that’s too small may not provide sufficient cooling, leading to overheating issues, while an oversized fan may not fit into your case, obstructing other components. Understanding how to measure CPU fan size will help you find the balance between cooling solutions performance and space management.

Understanding CPU Fan Measurements:

CPU fans are generally measured by their diameter, typically expressed in millimeters (mm). The most common sizes include 80mm, 92mm, 120mm, and 140mm. The measurement refers to the length of one side of the fan (as most are square), or the diameter of the fan blades themselves.

Key Components to Measure in a CPU Fan:

Fan Frame Size: This is the most important measurement. The fan frame size refers to the outer dimensions of the fan, typically in millimeters.
Fan Blade Size: The size of the blades can also give you an idea of how much airflow the fan can generate.
Mounting Hole Spacing: Fans are typically mounted using screws or other fastening mechanisms. To make sure your fan and CPU cooler work together, measure the distance between the mounting holes..
Fan Thickness: Another critical aspect to consider is the thickness of the fan. Most CPU fans have a standard thickness of either 25mm or 38mm. A thicker fan can push more air but might also require more space in your build.

Step-by-Step Guide to Measuring CPU Fan Size:

Step 1: Take off the fan or CPU cooler from the case.

Before you begin, make sure to power down your PC and disconnect it from the power source. Next, open your PC case and carefully remove the CPU cooler or fan. This gives you easy access to measure the fan properly.

Step 2: Measure the Diameter of the Fan

Using a ruler or caliper, measure the diameter of the fan from edge to edge. This is the key measurement that determines the fan size. Most CPU fans will be either 80mm, 92mm, 120mm, or 140mm. Be precise, as even small measurement errors can result in choosing the wrong fan size.

Step 3: Measure the Mounting Hole Distance

Fans have mounting holes that are used to attach them to the CPU cooler or case. The spacing between two adjacent mounting holes should be measured. This measurement ensures that the fan will fit snugly onto your CPU cooler or case without causing any installation issues.

Step 4: Measure the Fan Thickness

The fan’s thickness can also influence airflow and cooling performance. To measure the thickness, place your ruler or caliper between the front and back of the fan. This measurement is usually standard, but it’s essential to verify the thickness to avoid compatibility problems.

Step 5: Measure the Clearance in Your Case

Finally, you’ll need to measure the available space inside your PC case. Take note of how much room is available around your CPU cooler and nearby components. This will help ensure that the new fan will fit comfortably and won’t block airflow to other critical components.

Choosing the Right CPU Fan Size for Your Build:

Now that you’ve measured your CPU fan size, it’s time to select the best fan for your system. Different builds have varying cooling requirements depending on the CPU model, overclocking, and ambient temperature.

1. Smaller Fans (80mm and 92mm):

Smaller fans are typically quieter but may not provide as much airflow. These are ideal for compact builds with less space inside the case. However, they are less efficient at cooling higher-performance CPUs that generate more heat.

2. Larger Fans (120mm and 140mm):

Larger fans tend to push more air, making them ideal for high-performance builds where cooling is critical. However, they require more space inside the case and can be noisier, especially if running at higher speeds. A 120mm or 140mm fan is perfect for gaming rigs, workstations, and overclocked CPUs that need extra cooling.

Also Read: Can You Plug a Fan into a USB Header? A Comprehensive Guide!

CPU Fan Size and Airflow: How They Relate!

Fan size directly impacts the amount of airflow the fan can generate, which is crucial for dissipating heat from your CPU cooler. Larger fans typically move more air at lower speeds, which can result in quieter operation. Conversely, smaller fans may need to run at higher speeds to generate sufficient airflow, potentially creating more noise.

When selecting a fan, consider both the CFM (Cubic Feet per Minute) rating and the RPM (Revolutions Per Minute). CFM measures how much air the fan can move, while RPM indicates how fast the fan spins. A fan with a high CFM and low RPM will typically offer better cooling performance with less noise.

Additional Considerations for CPU Fan Selection:

While fan size is essential, there are other factors to consider when choosing the right CPU fan for your build:

Noise Levels: Look for fans with a lower decibel (dB) rating if noise is a concern. Larger fans with low RPMs can help reduce noise levels.
Bearing Type: Fans come with different types of bearings, such as sleeve, ball, or fluid dynamic bearings. Ball-bearing fans tend to last longer and offer better performance over time, while fluid dynamic bearings are quieter.
PWM vs. Non-PWM Fans: PWM (Pulse Width Modulation) fans allow for variable speeds, which can optimize both cooling and noise reduction based on CPU temperature. Non-PWM fans run at a constant speed.
RGB Lighting: For those interested in aesthetics, many modern fans come with RGB lighting that can be customized. However, this is purely cosmetic and has no impact on performance.

Conclusion: Measuring CPU Fan Size for Optimal Cooling

Accurately measuring your CPU fan size is crucial for ensuring compatibility and optimal cooling performance. Whether you are building a new PC or upgrading your existing setup, knowing the exact measurements allows you to choose a fan that will fit your system and provide the cooling performance needed to prevent overheating.

By following the steps in this guide, you can confidently select the right fan size for your CPU cooler and PC case. A properly sized fan will improve airflow, enhance cooling efficiency, and ultimately extend the lifespan of your components.

FAQ’s:

1. Why is it important to measure the CPU fan size?

Measuring the CPU fan size ensures compatibility with your CPU cooler and PC case. It helps maintain proper airflow and cooling, which is essential to prevent overheating and improve system performance.

2. What are the most common CPU fan sizes?

The most common CPU fan sizes are 80mm, 92mm, 120mm, and 140mm. These measurements refer to the diameter of the fan blades or the outer frame of the fan.

3. How do I measure the size of my CPU fan?

To measure your CPU fan size, follow these steps:

Measure the diameter of the fan from edge to edge using a ruler or caliper.
Measure the distance between adjacent mounting holes.
Measure the fan’s thickness to ensure compatibility with your setup.

4. What happens if I choose the wrong fan size?

If you select a fan that’s too small, it may not provide sufficient cooling, leading to overheating issues. If the fan is too large, it may not fit inside your PC case, causing space issues or blocking other components.

5. How does fan size affect cooling performance?

Larger fans, such as 120mm or 140mm, tend to move more air at lower speeds, improving cooling efficiency. Smaller fans, like 80mm or 92mm, may need to run at higher speeds to cool effectively, which can result in higher noise levels.

6. What is the significance of fan thickness?

Most fans are either 25mm or 38mm thick. Thicker fans can push more air but may require additional space in your PC build. Ensuring the correct thickness is important for both airflow and fitting the fan into your setup.

7. How can I ensure the fan will fit in my PC case?

After measuring the CPU fan, measure the available clearance in your PC case around the CPU cooler and adjacent components. This ensures that the new fan will fit without blocking airflow or other parts.

8. Should I consider noise levels when selecting a fan?

Yes, because they circulate more air at slower speeds, larger fans do tend to be quieter. Larger RPMs may cause smaller fans to produce greater noise. You can also look for fans with lower decibel (dB) ratings if noise is a concern.

9. What is a PWM fan, and do I need one?

PWM (Pulse Width Modulation) fans allow for variable speeds based on the CPU’s temperature. This optimizes both cooling and noise levels. If you want more control over your fan’s speed and noise, a PWM fan is a good choice.

10. Can I use RGB fans in my build?

Yes, many modern CPU fans come with RGB lighting. These fans add an aesthetic appeal to your build without compromising performance, though the lighting itself has no impact on cooling capabilities.

How to Measure CPU Fan Size: A Complete Guide!