A haemocytometer is a precision instrument used to count blood cells or other microscopic particles in a specific volume of fluid. It consists of a thick glass slide with a precisely engraved grid of known dimensions on its surface. A small volume of diluted blood or cell suspension is placed in a chamber on the slide, allowing cells to settle on the grid. Under a microscope, the number of cells in defined grid areas is counted, enabling calculation of cell concentration per unit volume. Haemocytometers are widely used in medical labs for blood analysis, cell culture, and reseach