A pipetting apparatus includes a pipetting head with a plurality of pipetting channels disposed in an arrangement pattern. Each pipetting channel includes a plunger and a cylinder. The plurality of pipetting channels includes at least two groups of pipetting channels with different diameters including a group of larger pipetting channels and a group of smaller pipetting channels. Each of the at least two groups of pipetting channels is disposed in an arrangement pattern in the pipetting head. Larger pipette tips communicate with the group of larger pipetting channels or smaller pipette tips communicate with the group of smaller pipetting channels.