4 meters long and 1 meter wide. Blackboard size: height should not be less than 1mm, width should not be less than 36mm in primary schools. Therefore, the blackboard in primary schools is 4 meters long and 1 meter wide. Blackboard is one of the necessary teaching tools in classrooms. The common types of teaching blackboards are traditional blackboards, color-coated steel board blackboards, new material composite blackboards, bracket movable blackboards, magnetic blackboards, interactive electronic whiteboards, glass blackboards, staff music blackboards, etc. Different blackboards have different characteristics.