Rat cage calculator
Check a cage before you buy it: two pet rats need at least 4 cubic feet, 2 per rat, which at 20 inches high means a floor of 2.4 square feet, about 26 by 13 inches. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Rats
- 2
- Cu ft per rat
- 2
- Volume cuft
- 4
- Volume l
- 113.267386368
- Volume m3
- 0.1132673864
Pet rats are social climbers that live in three dimensions, so a cage that only looks large on the floor can still fail them on volume. Rescue groups, first-time keepers, classroom animal programs, and breeders look up a rat cage calculator for the same reason: they need the minimum interior volume before they buy a multi-level cage, convert a ferret habitat, or reject a donated aquarium that photographs well and then crowds the animals. This tool takes one input — how many rats will share the enclosure — and multiplies a fixed two-cubic-foot allowance per rat. It returns the required volume in cubic feet, litres, and cubic metres, plus a suggested rectangular footprint at a twenty-inch interior height.
What two cubic feet per rat means and how the footprint is drawn
Minimum rat cage size is a volume problem, not a furniture guess from a pet-store aisle. Adult fancy rats climb, stand on their hind legs, and use hammocks and shelves, so the welfare floor that this rat cage calculator implements is a fixed interior volume of two cubic feet per rat.
That two-cubic-foot allowance is the long-standing North American fancy-rat community minimum: it is large enough that each animal has room to move, hide, and rest, and it is small enough that a first-time keeper can compare a listed multi-level cage, ferret habitat, or homemade wire box against a single number. The required volume is the head count multiplied by two cubic feet.
The same volume is also reported in litres and in cubic metres using the exact international foot, so a European litre listing and a United States cubic-foot listing can be compared without a second conversion step. A suggested footprint is then derived by dividing that volume by a twenty-inch interior height — high enough for a standing rat and a hanging hammock — and shaping the floor as a two-to-one rectangle, the aspect ratio of most commercial multi-level cages.
Two rats therefore require four cubic feet, a two-point-four square-foot floor, and a suggested plan about twenty-six inches by thirteen inches at twenty inches high. Many welfare groups recommend larger playpens and daily free-range time than this floor; this page reports the volume budget, not a luxury condo, so a rescue intake sheet and a shop spreadsheet can agree on the same cubic feet.
Where a rat cage calculator earns its keep
Rescue intake desks, first-time keepers, classroom animal programs, and small breeders look up a rat cage calculator because they need cubic feet from a head count, not a generic room-area tool and not a rabbit-hutch chart. A bed-size page answers how much floor a mattress occupies. A potting-soil page answers litres of mix.
A rabbit-cage page answers square feet by weight class. None of those searches is how large a cage two Dumbo rats need before the next adoption. Keepers use it to reject a twenty-gallon tank that looks roomy in a photograph and then fails the volume test once the pair is counted.
Teachers use it so students can check the two-cubic-foot rule without flipping a row by hand. Automation scripts that plan a rescue room or that fill a shop listing need a deterministic oracle, not a screenshot of a faded forum post. This page is not a rat-age human-year converter and it is not a pet-sitter rate card.
Invalid counts do not consume balance.
What you can do with it
First cage purchase
Enter how many rats will share a new enclosure to get the required cubic feet and a suggested length-by-width plan before you buy a multi-level cage.
Classroom two-cubic-foot rule
Let students submit a positive integer head count and verify that the product matches two cubic feet per rat without a rounding argument.
FAQ
How much cage volume does each pet rat get?
Each rat is allotted a fixed two cubic feet of interior volume. Two rats therefore need four cubic feet; four rats need eight. The allowance does not shrink as more animals arrive.
What happens if the rat count is less than one?
Zero, negative numbers, fractions, and non-numeric values are rejected and are not billed, because a cage cannot be sized for a non-integer rat.
Why does the calculator return a footprint as well as a volume?
Volume alone does not tell you how to cut a floor. The tool divides the required cubic feet by a twenty-inch height and shapes a two-to-one rectangle so a shop listing or a homemade box has a concrete length and width.
Is the minimum cage volume enough for my rats' welfare?
It is a floor, not a recommendation for luxury. Many welfare groups suggest a larger cage and daily time out of it; use this number to reject cages that are too small, then go bigger if you can.
Can I compare a cage that is listed in litres?
Yes. The required volume is also given in litres and cubic metres, using the exact international foot, so a European listing in litres and an American one in cubic feet can be checked against the same minimum.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/bio/rat-cage \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"rats":2}'const res = await fetch("https://api.kit.forhosting.com/bio/rat-cage", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"rats": 2
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/bio/rat-cage",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"rats": 2
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/bio/rat-cage", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"rats":2}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"rats":2}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/bio/rat-cage", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"rats": 2
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "bio.rat_cage",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_rats | 100 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
A count below one is rejected as invalid_input instead of inventing a cage for a fraction of an animal.
Input contract, response shape, and error behaviour
On success the body echoes rats, reports the fixed two-cubic-foot allowance per rat, the required volume in cubic feet, litres, and cubic metres, the suggested floor area in square feet and square metres, and the suggested interior length, width, and height in inches. Example: two rats yield four cubic feet because each rat is allotted two cubic feet, and the twenty-inch height turns that volume into a two-point-four square-foot rectangle. Failed validation is not billed. The same one-field contract is what the free browser form posts, so a check you type by hand matches an automation call on the same count. POST a JSON body with one required field: rats, a positive integer head count no greater than one hundred. The count may arrive as a JSON integer or as a whole-number string; fractions, zero, negatives, empty strings, and a missing key fail with invalid_input naming rats and stating that a positive integer is required. Aliases the field accepts include count, n, and rat_count, so a barn script that already stores n does not have to rename the key. The formula field restates the product and the footprint division; formula_applied substitutes the numbers so a worksheet can print the arithmetic next to the answer. Pair the numbers with your own drawing if you need a sketch of bars and ramps; this endpoint computes volume and a suggested footprint only and does not emit bar-spacing charts, wheel diameters, or bedding volumes.
Where a rat cage calculator earns its keep
Pin volume_cuft in tests, keep the head count a positive integer, and you get the same four cubic feet for two rats in a lecture notebook, an LMS plugin, and a rescue spreadsheet.
Integration use cases
Rescue intake and listing checks
Reject a donated tank or undersized wire box by counting the rats and comparing the returned volume_cuft to the measured interior of the candidate cage.
Technical questions
How do I calculate rat cage size from the number of rats?
Send rats as a positive integer. The API returns volume_cuft equal to the head count times two cubic feet, plus litres, cubic metres, and a suggested 2:1 footprint at a twenty-inch interior height.
What does the rat cage calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.