Guinea pigs look small, but they love to trot, "popcorn" (jump straight up when they are happy) and dash between hiding places. Welfare groups agree that a tiny cage is not enough, and that they should live with at least one guinea pig friend, because they are social animals (RSPCA).
The tricky part is that groups give their numbers in different ways, and shop labels are often smaller than what vets and charities suggest. This guide puts the published minimums side by side and lets you check your own set-up.
| Source | Suggested minimum |
|---|---|
| Blue Cross | Outdoor hutch of no less than 5 ft x 2 ft (about 152 x 61 cm), plus a run of at least 6 ft x 4 ft (about 183 x 122 cm). Indoors with no separate run: a living area of at least 6 ft x 4 ft. |
| PDSA | A hutch of at least 1.5 x 1 m with a run of at least 2 x 1 m attached. Bigger is better. |
| RSPCA | No fixed measurements, but a traditional hutch should not be the only permanent home. Space must be high enough to rear up and stretch out, with a large exercise area. |
These sources don't give a per-animal rule, so treat the numbers as the floor for a pair and give three or four guinea pigs clearly more. If your set-up is smaller than the figures here, that is a reason to upgrade it, not a reason to feel bad.
More floor beats more floors. Guinea pigs have short legs, so one big level is better than a tall tower of ramps.
Guinea pigs move in short bursts all day. With only a little room, they cannot get away from each other or from something that scares them, and they cannot run. Blue Cross points out that short legs make multi-level hutches hard to use, and that any ramp needs protective sides so nobody slips off.
Temperature matters too. The RSPCA says room temperatures of 17-20 °C are ideal indoors, that they should come inside when it drops below 15 °C, and that heatstroke is a risk above 26 °C. PDSA gives slightly different figures (comfortable below 24 °C, heatstroke risk above 27 °C). Where sources differ, keep the home on the cooler, shadier side.
If a guinea pig is limping, sits hunched, stops eating or has sore feet, ask a vet. This guide is about housing, not health, and a vet can't be replaced by a calculator.