Measure nose to tail base once and get the inside size of a round, flat, covered or perch bed, matched to how your cat sleeps, plus how many beds a multi-cat home needs.
Cat Bed Size Calculator - Inside Size for Any Cat Bed
Measure nose to tail base once and get the inside size of a round, flat, covered or perch bed, matched to how your cat sleeps, plus how many beds a multi-cat home needs.
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Cat bed size from one tape measure
What size cat bed should you buy? Measure the cat from the nose to the base of the tail and add 2 to 4 inches. An 18 in cat that sleeps curled up fits a round bed of 20 in inside diameter; the same cat sprawled out wants 22 in or more. The calculator does that arithmetic for round, flat, covered and perch beds, scales a bed for two or three cats, counts how many beds the household needs and checks a window perch against its weight rating.
The measurements and choices the form asks for
- Units - inches and pounds, or centimeters and kilograms. The result always shows both.
- Nose to base of tail - measured with a soft tape while the cat is relaxed. Leave the tail out.
- Sleeping style - curled in a ball, on its side, sprawled flat, or a mix. Go by how the cat sleeps most of the time.
- Bed type - round or donut bed, flat cushion or mat, covered cave, or a window perch, shelf bed or hammock.
- Sleeping footprint - optional. Length and width of the cat asleep in its usual position. With it the result also gives a width.
- Cats sharing this bed and cats in the home - the first scales the bed, the second sets how many beds to buy.
- Age and mobility, weight and perch rating - optional. Kittens and stiff older cats get a note on height; perches get a weight check.
Why the bed is the cat plus a few inches
The sizing rule comes from the PetSmart cat bed guide: measure from the nose to the base of the tail while the cat is relaxed and add two to four inches for a comfortable fit. The same guide splits cats by how they sleep. A cat that curls up wants a snug bed whose sides touch it, and a cat that sprawls needs a bigger one so no paws hang over the edge.
The calculator turns that into one number. A curler gets the bottom of the range, +2 in. A side sleeper gets the middle, +3 in. A cat that changes position, and anything you buy as a perch, gets the top, +4 in. The choice of point inside the range is the calculator's own assumption, and the result prints the whole range next to it, so you can see where a bed you like falls.
For a sprawler the nose to tail base length is only a floor. Front legs stretched forward and back legs pushed out add length that the tape did not measure. That is why the form has a second, optional measurement: the footprint of the cat asleep. When you enter it, the allowance goes on both its length and width and the bed follows the cat as it actually lies.
One more thing about the number. It is the inside size. Check whether a listing gives the inside or the outside dimensions; a plump bolster or the walls of a cave take part of the outside size.
Round bed inside diameter for cats from 12 to 24 inches
Nose to tail base in inches, and the inside diameter the calculator returns for a single cat in a round bed. Bed sizes in centimeters are rounded up to the whole centimeter, the cat lengths to the nearest one.
| Cat, nose to tail base | Curls up (+2 in) | Side sleeper (+3 in) | Varies or sprawls (+4 in) |
|---|---|---|---|
| 12 in (30 cm) | 14 in (36 cm) | 15 in (39 cm) | 16 in (41 cm) |
| 14 in (36 cm) | 16 in (41 cm) | 17 in (44 cm) | 18 in (46 cm) |
| 16 in (41 cm) | 18 in (46 cm) | 19 in (49 cm) | 20 in (51 cm) |
| 18 in (46 cm) | 20 in (51 cm) | 21 in (54 cm) | 22 in (56 cm) |
| 20 in (51 cm) | 22 in (56 cm) | 23 in (59 cm) | 24 in (61 cm) |
| 22 in (56 cm) | 24 in (61 cm) | 25 in (64 cm) | 26 in (67 cm) |
| 24 in (61 cm) | 26 in (67 cm) | 27 in (69 cm) | 28 in (72 cm) |
For a sprawler the last column is the minimum, not the answer. Measure the sleeping footprint to size past it.
One bed for two or three cats
For a shared bed the calculator keeps the area per cat constant, so each side grows by the square root of the number of cats: 1.41 for two, 1.73 for three. That scaling is an assumption about geometry, not a figure from a guideline. Example: a cat of 18 in nose to tail base, round bed.
| Cats in the bed | Curlers | Side sleepers | Mixed positions |
|---|---|---|---|
| 1 | 20 in (51 cm) | 21 in (54 cm) | 22 in (56 cm) |
| 2 | 28.5 in (72 cm) | 30 in (76 cm) | 31.5 in (80 cm) |
| 3 | 35 in (88 cm) | 36.5 in (93 cm) | 38.5 in (97 cm) |
What the feline environment guidelines say about beds
The American Association of Feline Practitioners and the International Society of Feline Medicine published joint guidelines on what a cat needs at home. Resting and sleeping areas are one of the key resources, and several points in them change what you buy.
Who measures a cat before buying a bed
Three typical cases, with the numbers the calculator returns for them.
Cat bed sizing questions
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