A particle size analyzer, also known as a particle sizer, is used to measure the sizes of particles in a sample. It can also determine distributions of particle sizes.

Particle sizing systems are used for research (such as for proteins or other biomaterials), manufacturing (such as for cosmetics), and quality control applications (such as food safety and pharmaceuticals). Different types of particle size analyzers are designed for different purposes; for example, particles can be solids, such as in a powder form, but can also take the form of liquids or aerosols.