Easy Separation of Stacked Chairs
Plastic chairs are ubiquitous in everyday life. You’ll find them in schools, cafes, street-side eateries, and homes across the globe. Have you ever wondered why these chairs often feature a circular hole in their center? It’s not just for show—this design feature serves multiple purposes.
Firstly, the hole facilitates easy separation of stacked chairs. When chairs are stacked, the pressure of the air between them creates a vacuum, making it difficult to pull them apart. This phenomenon is similar to the Magdeburg hemispheres experiment, where two teams of horses, each pulling on a set of airtight hemispheres, were unable to separate them due to the vacuum created inside.
The hole in the center of plastic chairs alleviates this issue by providing an escape route for the air, making it effortless to separate them. Additionally, this hole serves as a convenient grip for users to lift and move the chairs.

The primary purpose of the hole is to easily separate stacked chairs.
Enhanced Load-Bearing Capacity
Plastic chairs are designed with a certain degree of flexibility. When someone sits on the chair, the four corners expand in all directions. The central hole plays a crucial role in accommodating this expansion, thereby increasing the chair’s load-bearing capacity.
The size of the hole is carefully considered—not too big, not too small. This ensures adequate air circulation without compromising the chair’s structure and durability. A larger hole or multiple holes could weaken the chair’s strength, making it more prone to breakage. Conversely, a smaller hole might hinder the easy separation of stacked chairs.
The circular shape of the hole is also intentional. Unlike shapes with corners, such as squares or triangles, the circle distributes pressure evenly, reducing the risk of breakage. Moreover, a circular hole is safer for users who might insert their fingers into the hole to separate the chairs.

The circular hole in plastic chairs serves an important purpose.
Ventilation and Easy Transport
The central hole in plastic chairs also enhances ventilation, making prolonged sitting more comfortable. Additionally, during transportation, the holes can be utilized to thread a rope through, securely fastening a stack of chairs together and preventing them from toppling over or falling during transit.
Cost Savings
From a manufacturing perspective, the inclusion of a central hole in plastic chairs results in a slight reduction in material costs. While the savings per chair may seem negligible, they can accumulate significantly when producing chairs on a large scale.
Furthermore, during the manufacturing process, the central hole simplifies the task of removing the chairs from their molds.
The Secret Purpose of the Small Circular Hole in Plastic Chairs: Unveiling the Unknown
Have you ever wondered why plastic chairs often have a round hole in the center? Well, wonder no more! There are several reasons behind this curious design feature, and we’re here to reveal them all. Get ready to uncover the fascinating secrets behind those ubiquitous holes and gain a whole new appreciation for the humble plastic chair.