Different toner powders have different densities. For example, a finer toner will have a lower density than a toner made up of larger particles. Because of this lower density, the weight of the amount of toner powder for laser toner cartridge will be less than if the toner was less dense (i.e. coarser). The amount of toner that we include in a bottle is in accordance with how much of our formulation of toner you would need to refill the cartridge and get a full page yield out of it. The density of the toner also affects how much toner will need to be picked up by the PCR roller during the printing cycle; if your toner powder is finer, you will tend to need less of it weight-wise to obtain an even coverage over the printed area.