Minimum: 2-2.5 cubic feet per rat.
Pet rats need at least 2 cubic feet (3,456 cubic inches) per rat — more is always better. Rats are social and must be kept in pairs or groups of the same sex. Wire cages with solid floors are ideal — provide shelves, hammocks, and climbing structures for enrichment. Bar spacing: 0.5" for adult rats (smaller for babies to prevent escape). Minimum floor space: 2 sq ft for 2 rats. Height is important — rats love climbing; multi-level cages are preferred. Avoid aquariums (poor ventilation → ammonia buildup). Bedding: paper-based or aspen; avoid cedar and pine (toxic phenols). Clean cage weekly, spot-clean daily. Rats are highly intelligent and need daily interaction and enrichment.