You can find a range of capacities in front load models as well as top-load impeller and agitator models. Capacity is measured in cubic feet. Here is a snapshot of approximately how much laundry different capacities can hold—note that these averages can vary based on the design of the washer model:
Small Capactity Machine
3.5 cubic feet-4.4 cubic feet
Hold approximately 9-15 full size bath towels
Medium Capactity Washing Machine
4.5 cubic feet-4.9 cubic feet
Hold approximately11-19 full sized bath towels
Large Capacity Washing Machine
5.0 cubic feet-5.3 cubic feet
Holds approximately 12-21 full size bath towels