Ensure your rats have enough space to thrive based on the 2 cubic feet per rat rule.
Inches (in)
Centimeters (cm)
Total Volume: cubic feet
Recommended Max: Rats
function updatePlaceholders() {
var unit = document.getElementById("unit").value;
var w = document.getElementById("width");
var d = document.getElementById("depth");
var h = document.getElementById("height");
if (unit === "cm") {
w.placeholder = "cm";
d.placeholder = "cm";
h.placeholder = "cm";
} else {
w.placeholder = "in";
d.placeholder = "in";
h.placeholder = "in";
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function calculateCageCapacity() {
var width = parseFloat(document.getElementById("width").value);
var depth = parseFloat(document.getElementById("depth").value);
var height = parseFloat(document.getElementById("height").value);
var unit = document.getElementById("unit").value;
var resultDiv = document.getElementById("rat-result");
var volumeDisplay = document.getElementById("volume-val");
var countDisplay = document.getElementById("rat-count");
var safetyNote = document.getElementById("safety-note");
if (isNaN(width) || isNaN(depth) || isNaN(height) || width <= 0 || depth <= 0 || height <= 0) {
alert("Please enter valid dimensions for all fields.");
return;
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var cubicFeet;
if (unit === "cm") {
// Convert cm to inches first (1 cm = 0.393701 inches)
var wIn = width * 0.393701;
var dIn = depth * 0.393701;
var hIn = height * 0.393701;
cubicFeet = (wIn * dIn * hIn) / 1728;
} else {
// Calculation in inches
cubicFeet = (width * depth * height) / 1728;
}
// Standard rule: 2.0 cubic feet per rat
// Some experts say 2.5 for larger males, we use 2.0 as the base standard.
var maxRats = Math.floor(cubicFeet / 2);
// Logic for single rat (rats are social, always recommend 2+)
var displayedRats = maxRats;
if (maxRats < 2) {
displayedRats = maxRats < 1 ? 0 : 1;
}
volumeDisplay.innerText = cubicFeet.toFixed(2);
countDisplay.innerText = displayedRats;
var noteText = "Rats are social animals and should always be kept in pairs or groups. ";
if (displayedRats < 2) {
noteText += "Warning: This cage is too small for a pair of rats. Consider a larger habitat.";
} else {
noteText += "Ensure bar spacing is 0.5 inches for females/babies and no more than 1 inch for adult males.";
}
safetyNote.innerHTML = noteText;
resultDiv.style.display = "block";
}
How Much Space Does a Pet Rat Really Need?
Pet rats are intelligent, active, and highly social creatures. Unlike smaller rodents, they require vertical space for climbing and significant horizontal space for foraging and exercising. When choosing a cage, the "Golden Rule" of rat keeping is to provide at least 2 to 2.5 cubic feet of space per rat.
Understanding the Calculation
To calculate the capacity of a cage, you must find the total volume in cubic inches and convert it to cubic feet. This is done by multiplying the Width x Depth x Height (in inches) and dividing the result by 1,728.
Example:
A cage measuring 24″ wide, 18″ deep, and 36″ high:
24 x 18 x 36 = 15,552 cubic inches.
15,552 / 1,728 = 9 cubic feet.
9 / 2.0 = 4.5. This cage can comfortably house 4 rats.
Beyond Just Volume: Critical Factors
While volume is a great starting point, a cage must meet other physical requirements to be safe and humane:
Floor Space: Volume isn't everything. A very tall but extremely narrow cage (like a bird flight cage) might not provide enough continuous floor space for wrestling and running.
Bar Spacing: For young rats or females, bar spacing should be 0.5 inches (1.27 cm) or less to prevent escapes. Adult males can often be housed with 1-inch spacing.
Ventilation: Aquariums and glass tanks are generally unsuitable for rats. Rats have sensitive respiratory systems, and the ammonia from their urine builds up quickly in tanks. Always use a wire cage.
Solid Flooring: Avoid wire-mesh floors and balconies, as these can cause "bumblefoot," a painful infection on the foot pads. If your cage has wire floors, cover them with fleece, linoleum, or plastic mats.
The Social Requirement
Rats are "obligate social" animals. Keeping a single rat is widely considered inhumane as it leads to depression and behavioral issues. Even the largest cage in the world cannot replace the companionship of another rat. Always plan for a minimum of two rats when using this calculator.