The gear pump is compact, simple to operate and has a limited number of moving parts. The gear pump cannot match the pressure generated by the reciprocating pump or the flow of the centrifugal pump, but provides higher pressure and throughput than the vane or cam pump. Internal gear pumps have better suction capacity than external gear designs and are more suitable for high viscosity fluids, although their effective operating range is from 1 cP to over 1,000,000 cP.

Since the output is proportional to the speed, internal gear pumps are typically used for metering and mixing operations. The low internal volume reliably measures the liquid passing through the pump for precise flow control.

Internal gear pumps can be designed to handle corrosive liquids. Although they are usually made of cast iron or stainless steel, the new alloys and composites enable the pump to handle corrosive liquids such as sulfuric acid, sodium hypochlorite, ferric chloride and sodium hydroxide.