There are  a few different factors to consider when choosing a chair for your classroom
Size - take into consideration the age and average height of the students in your class, and choose chairs accordingly. As a guide, children should be able to place their feet on the floor when sitting back against the backrest of the chair.
Style - From stackable chairs to swivel chairs to stool chairs, there are a variety of different styles to choose from. Think carefully about which will work best for your students. Younger children, for example, would benefit from the stability and safety of a chair with a back support. You also might prefer not to introduce a swivel chair into a classroom of younger or easily distractible students!
Design - if you want to create a coordinated look for your classroom, choose a chair design that matches with your other classroom furniture. This might be in colour or material.
See our blog Choosing The Right Classroom Table & Chair Height for more information.