The complete rat cage setup guide

Rat cage size by number of rats

Bigger is always better, but there are firm minimums. A cage that is too small causes stress, and free-roam time cannot make up for it. In the UK, the Animal Welfare Act 2006 puts a legal duty on owners to provide a suitable environment: a cage that meets your rats' physical and behavioural needs, not just one that fits in the corner of the room. These are separate welfare recommendations, not one legal standard or a per-rat formula. Choose the larger practical home and check fall protection, access and your rats' needs.

Where the sources differ, we follow the bigger Blue Cross size for two to five rats. The PDSA adds a handy shortcut: cages sold for ferrets and chinchillas are usually a good size for rats, as long as the rats cannot squeeze between the bars. Check your own measurements with our rat cage size and fit calculator.

• Choose the cage first, then buy accessories around its measurements
• Keep movement space open so the cage does not get cluttered
• Use more than one hide and feeding point for a group

Rat cage for 2 rats: what size do you need?

Two rats need at least 80 × 50 × 80 cm (31.5 × 20 × 31.5 in), which is Woodgreen's minimum for up to four rats. Blue Cross recommends 90 × 60 × 120 cm (35 × 24 × 47 in) for two to five, and we would choose that if you have the room. Measure the usable inside space, not the outside of the box or the stand.

Height needs usable routes. Blue Cross's 120 cm (47 in) height only helps if your rats can use it: arrange levels so there is always a shelf, hammock or ramp within easy reach, with no long drops. Many owners start with two rats and add a third later, which is one more reason to buy for the bigger size. Woodgreen recommends groups of three or more, so a single rat is less likely to be left alone later.

Rats grow fast. A cage that fits two young rats at 6 weeks will feel cramped by 12 weeks, so buy for adult size from the start. Adult males weigh around 500 g (1.1 lb) and females around 300 g (10.5 oz) (NFRS).

Best rat cage: what makes a good one?

A good rat cage is large, wire-sided, escape-proof and easy to clean, with a solid floor, narrow bars and big doors. Start with ventilation, secure doors and the floor. Check every gap against your smallest rat, including corners and feeding doors; a cage sold for another species is not automatically suitable. Large doors matter because you must reach the back to clean and lift out a resting rat without taking everything apart.

Wire cage or glass tank?

Always choose a wire-sided cage over a glass tank or plastic vivarium. Rat urine releases a lot of ammonia, which can cause breathing illness (PDSA), and a tank traps it at floor level where rats breathe. Wire sides let air move through the whole cage. The PDSA warns that poor airflow can lead to severe lung problems.

Horizontal or vertical bars?

Horizontal bars are better for climbing. Rats grip them naturally and use them as ladders around the cage. Vertical bars are harder to grip and offer less to do. Most purpose-built rat cages use horizontal bars for this reason.

Rat cages in the UK: a quick fit check

• Bar spacing: 1 cm (0.4 in), checked at doors and corners as well as the sides
• Floor space: room to stretch, turn and climb, not just somewhere to sleep
• Floor: solid base and solid or covered shelves
• Doors: big enough to reach every corner
• Zones: bed, food, water and toilet area apart, so there is always a clean corner
• Room: away from sunlight, radiators, draughts, speakers and other pets

Bar spacing for rats

Bar spacing for rats should be 1 cm (0.4 in, just under half an inch). Woodgreen gives 1 cm for every size of group, and the RSPCA's rule is that no rat should be able to push its head through, because once the head fits, the body follows. Anything wider and young rats, small females and dwarf rats can squeeze out.

The safest approach is to buy a cage with 1 cm bar spacing from the start. Check every gap against your smallest rat; a stated spacing alone does not guarantee every cage is secure.

If your cage has wider spacing and you have young rats, you can fix mesh panels to the inside with cable ties for now. Check every join. Rats are persistent and surprisingly flexible.

Before buying accessories, check that bowls, shelves, hides and fittings suit the bar spacing and fix on firmly without sharp or wobbly edges. Use our rat vision guide to plan shelter, light and clear routes between levels.

How to set up a rat cage step by step

Start with the cage itself, then build the layout in layers. A good rat cage gives clear sleeping places, safe movement, food and water, foraging, and enough open space for rats to move away from each other.

1. Choose and place the cage. Pick a roomy, wire-sided cage with 1 cm bars, a solid floor and easy cleaning access. Put it in a room at 19 to 23°C (66 to 73°F), raised to table height, away from sunlight, radiators, draughts and speakers.
2. Add bedding. Cover the base with a generous layer of low-dust, paper-based bedding (substrate) that absorbs well. Compare options in our rat bedding guide.
3. Add resting spots. Fit one more hide than you have rats, spread across levels, so one rat cannot guard the only good bed. Add two or more hammocks up high.
4. Build movement paths. Use ledges, shelves and ropes to link levels from floor to roof, staggered, with no long drops.
5. Set up food and water. Add two water points at different ends or levels (Woodgreen), plus a heavy bowl or bar-fixed feeder away from the toilet corner.
6. Add a litter tray. Put one to three corner trays of unscented paper pellets where your rats choose to toilet, often under a favourite hammock (Woodgreen).
7. Add one foraging job. A scatter-feeding patch or a foraging cup comes before any decorative pieces.
8. Weekly reset. Rotate small enrichment, keep core sleeping places steady, and clean before smells build up.

Rat cage setup ideas: hides, shelves or hammocks first?

You need all three, because each does a different job. A hide is for sleeping and feeling safe. A shelf adds climbing routes and extra levels. A hammock is a soft resting spot off the floor.

Start with hides, then shelves, then a hammock. Keep open floor space so the cage never feels crowded. The RSPCA gives the same advice: hiding, climbing and investigating places at different heights, without filling the whole cage. Read more in our rat hammock guide and our guide to rat houses and hides.

Is there a starter set for a new rat owner?

• Fairy Mushroom Rat Cage Accessory Kit: one mushroom hide, two climbing shelves and three hanging foraging cups.
• Leaf Rat Cage Set: one cupped leaf hammock and two leaf shelves.
• Bee and Honeycomb Rat Cage Set: one hive hide, three honeycomb shelves and three bee foraging cups.
• Cloud Rat Cage Shelves and Hideaway Set: one enclosed hideaway and three climbing shelves.

Choosing the right bedding for a rat cage

Use a paper-based bedding or a washable fleece liner, and never cedar or pine chips, sawdust, newspaper or cotton wool (PDSA). Bedding directly affects breathing health. Respiratory infection is one of the most common problems in pet rats, and Woodgreen lists dusty bedding, poor ventilation, stress and temperature swings as things that make it worse. Ammonia from urine is a big trigger, so your bedding and cleaning routine are the first line of defence.

Corncob bedding is sold for small pets but is not on the lists from the RSPCA, PDSA or Woodgreen, so we would choose a paper-based bedding instead. The RSPCA also asks you to avoid over-absorbent, fragranced or coloured bedding. For a full side-by-side, see our rat bedding comparison.

Bedding depth and nesting material

The RSPCA asks for a generous layer of bedding in the cage, plus a digging box outside it. Choose the depth and container for your own rats and keep it clean. For nesting, offer white tissue paper, shredded paper, paper strips or dust-extracted hay so rats can build their own nests (RSPCA, Woodgreen). Never use cotton wool or fluffy bedding: the threads can wrap around toes and cut off circulation, and cause gut blockages if eaten (RSPCA, PDSA). Our rat digging box guide covers the dig area.

Essential rat cage accessories checklist

Every cage needs sleeping spots, food and water stations, climbing routes and enrichment. These are necessities, not extras.

The non-negotiables

• Two water points: bottles or securely fixed bowls, at each end or on two levels (Woodgreen); check daily that bottles release water
• Food bowl: heavy and low, or fixed to the bars so it cannot tip
• Hammocks: two or more, because rats sleep in groups and like choice
• Enclosed hides: one more than the number of rats, each with more than one exit (RSPCA)
• Litter trays: one to three corner trays with unscented paper pellets (Woodgreen)
• Solid shelves or platforms: wire shelves covered to prevent bumblefoot

Climbing and enrichment

• Ropes and ladders: natural fibre such as cotton, replaced when worn (RSPCA)
• Tubes and tunnels: wide enough for an adult to turn; 10 cm (4 in) pipe works as a nest tube (Rat Guide)
• Foraging toys: scatter-feeding spots, treat puzzles, paper bags to shred
• Dig box: a container of coco coir, shredded paper or clean compost
• Gnawing branches: fruit wood such as apple, untreated (RSPCA); see our safe wood for rats guide

What to avoid

• Wheels under 30 cm (12 in) across, or with rungs or mesh. Small wheels bend the spine and mesh catches feet. If you add a wheel, Woodgreen asks for an extra-large solid one at least 12 inches across. See our guide to rat wheels.
• Cotton wool or fluffy bedding. Fibres wrap around toes. Use paper-based nesting instead.
• Anything with small removable parts. Rats chew everything. If a piece can come off and be swallowed, remove it.
• Exercise balls. The RSPCA says never put rats in them.

Rat cage layout: zones that work

Layout tips

Work from the bottom up. Leave an open floor route, then add low resting places and connected climbing routes. Break up long drops with firmly fixed resting surfaces, without turning the inside into an obstacle course. Picture a sleepy rat travelling from bed to water: that journey should not need a leap. Leave room around every entrance for a rat to turn and for you to check inside.

Space hides apart. If every bed is in one area, a dominant rat can guard them. Spread hides across levels so every rat has somewhere to go.

Cover wire shelves and ramps. Bare wire underfoot causes bumblefoot (pododermatitis). Cover with fleece, lino offcuts or rubber shelf liner, and secure the edges so rats cannot pull them up.

Create sight breaks. Rats sometimes need to be out of each other's sight. Use hides, tubes and hammocks as visual barriers; the RSPCA recommends this to reduce squabbles in groups, and it helps during introductions.

Place the cage carefully. Keep it out of direct sunlight and away from radiators, draughty windows and speakers. The RSPCA gives 19 to 23°C (66 to 73°F) as ideal and the PDSA gives 20°C (68°F). Avoid humidity extremes such as bathrooms or air-conditioned rooms (RSPCA). Our rat temperature guide covers hot and cold days.

Where should food, water and the litter tray go?

Put water within easy reach in more than one part of the cage, and check each bottle actually releases water. Put feeding spots away from the usual toilet corner. Watch the group rather than assuming a full bowl means everyone ate: a confident rat can take over a favourite station. Keep fresh food where you can reach it to remove leftovers, and do not let it get buried in a hide.

Rat cage setup ideas for different rats

What should a rat cage have in it?

Plan for resting, exploring, climbing, nesting and searching for food. A hide and a hammock do different jobs, so offer choices instead of one compulsory bed. Cheap cardboard activities can sit alongside longer-lasting accessories. Add one new item at a time and watch how the group uses it before changing the whole layout. A beautiful theme is a bonus; access and inspection come first. For more ideas, see our 35 rat enrichment ideas and what a rat cage should have in it.

How do I adapt the cage for older rats?

Lower favourite beds and put food, water and a bed on the same easy level when climbing gets hard. Replace steep routes with gentle, supported ramps. Keep familiar landmarks rather than moving everything overnight. A change in movement can also come from illness or pain, not just age: see an exotics vet about new weakness, falls or reluctance to move. Our rat life stages guide covers senior care.

Quick comparison

Common rat cage mistakes to avoid

Buying a cage that is "big enough for now". Rats grow fast. Buy for adult size and the group you will have, not the two babies you bring home.

Relying on free roam to make up for a small cage. Free roam is brilliant, but rats spend most of their lives in the cage. An hour out does not undo 23 hours in a cramped space.

Putting the cage on the floor. Rats are prey animals. Foot traffic, other pets and movement overhead are stressful. Raise the cage to table height.

Cleaning too hard. Scrubbing every surface with strong disinfectant strips away your rats' scent and can lead to more scent marking. Spot clean daily, clean the whole cage weekly (RSPCA, PDSA), and put back a handful of clean, used nesting material so it still smells like home. Never use air fresheners or strongly scented products near the cage (RSPCA). Our rat cage cleaning guide has the full routine.

Skipping hygiene for second-hand kit. Clean and disinfect second-hand cages and accessories before use. For new rats, the NFRS advises at least two weeks with no signs of illness, kept where they do not share air with your own rats, before introductions. See our quarantine cage guide.

Keeping one rat. The PDSA says rats cannot live alone. If you have lost a cage mate, read our guide to what to do for a lone rat.

Rat cage calculator and other tools

Use our rat cage size and fit calculator to check your cage's measurements against the welfare sizes above. Enter the inside width, depth and height and your number of rats. Treat any calculator as a planning aid, not proof that a cage meets every need: check the usable base, safe routes and your group.

If you are buying for a new setup, start with our pet rat supplies guide and first 30 days with pet rats, then come back here to plan the cage. Our pet rat care hub links every rat guide we have. This guide is general care advice from people who keep pet rats ourselves; it does not replace a vet.