Seat height
Seat height from the ground. In most modern chairs and stools, this height is 48 - 50 cm - this value is considered suitable for adults of almost any physique. Bar stools are often made taller - up to 90 cm or even more; this is due to the specifics of the application. Such products can be height adjustable.
Back height
The height of the back of the chair relative to the seat. In modern chairs, this height is most often not particularly large — from 30 to 60 cm. At the same time, backs less than 40 cm high are actually purely symbolic — they provide almost no support for the back. An indicator of 40 – 50 cm is average, and a person of average height can lean on the back of more than 50 cm with almost his entire back.
Chair height
The overall height of the chair is from the floor to the top. In models without backrest, this dimension actually corresponds to the height of the seat (see above). If there is a back, it determines the overall dimensions of the chair; this information is rarely required, mainly for storage or transport.
Max. load
The maximum allowable load for a given chair, in other words, the maximum weight that it can normally withstand.
Note that modern chairs usually have a margin of safety, and if the weight is exceeded, it is likely that the product will not break immediately. However, it is still impossible to allow such an excess: under an off-design load, the chair will wear out a lot, and a breakdown can occur at any time — including later, under a completely acceptable weight.