How many gallons does a bathtub hold? That depends on how big the tub is and how high you fill it with water.
Measure the Inside of the Tub and Multiply
You can easily determine the maximum capacity of your bathtub.
You can calculate the maximum capacity of a bathtub by measuring the total volume of the tub.
Simply multiply length x width x depth (all measured on the inside of the bathtub) to find out how many cubic feet there are in your tub.
There are roughly 7.5 gallons per cubic foot, so if you want to know your bathtub capacity in gallons, multiply the cubic feet by 7.5.
For example, if the inside of your tub is 5 feet long, 2 feet wide, and 1 foot deep, your bathtub’s maximum capacity is 5 x 2 x 1 = 10 cubic feet.
You can convert your cubic feet into gallons by multiplying by 7.5, in this instance 10 x 7.5 = 75 gallons maximum capacity.
These figures are the maximum capacity. If you only fill the tub to a depth of 1/2 foot the math becomes 5 x 2 x 1/2 = 5 cubic feet. Therefore you can calculate how much water is in your tub for any depth that you choose.
What Is The Average Capacity Of A Bathtub?
The average capacity of a standard “drop in” bathtub is 42 gallons.
Smaller tubs, like those added to small bathrooms or those squeezed in to a corner, may hold only 30 to 40 gallons.
Many tubs, however, will hold up to 60 gallons.
On the other hand, a jetted tub will likely hold 75 gallons or more, and an oversized 72 inch clawfoot tub may hold 100 gallons of water.
The capacity of a bathtub can vary depending on the type or style of tub.
Clawfoot Tubs
A clawfoot tub is a type of bathtub that has a claw-like foot at one or both ends. These feet are used to hold the tub in place when it is installed.
Clawfoot tubs have been around for centuries and were popular during the Victorian era. They are often made of cast iron or acrylic and can be quite large.
Most clawfoot tubs hold about the same amount of water as modern tubs, in the 40 – 60 gallon range. This is for clawfoot tubs that are roughly 54 – 62 inches long.
However, one highly prized class of clawfoot tubs are called oversized clawfoot tubs. These tubs are about 72 inches long and typically hold 75 to 100 gallons of water!
Freestanding Tubs
Freestanding tubs are another type of bathtub that is becoming increasingly popular. They are similar to clawfoot tubs in that they are not attached to any walls or floors
Freestanding tubs come in various shapes and sizes, but they typically have the same capacity as normal modern bathtubs.
Corner Bathtubs
Corner bathtubs are a type of bathtub designed to fit into a corner. They are often triangular in shape and have one or two curved ends
Because they are designed to fit into a corner, corner bathtubs typically have lower average capacities than other types of bathtubs. For example, a corner bathtub that is forty-eight inches long and thirty-six inches wide may only hold thirty gallons of water.
Alcove Tubs
Alcove tubs, also called recessed tubs, are a type of bathtub designed to fit into an alcove. An alcove is a recessed area with walls on three sides.
Alcove tubs are typically rectangular in shape and have straight sides. This makes them perfect for fitting into an alcove.
Because they are designed to fit into a specific space, some alcove tubs have lower average capacities than other types of bathtubs. Smaller alcove tubs may hold only 30 gallons of water.
Drop-In Tubs
Drop-in tubs are the most common type of bathtub. They are rectangular in shape and fit into a pre-existing bathtub opening
“Standard” drop-in tubs have an average capacity of 42 gallons.
Bath vs. Shower: Which One Uses More Water?
People often wonder how much water is used when taking a bath versus taking a shower. This varies on the size of the tub, the capacity of the shower head, and how long a shower lasts.
A standard showerhead typically uses two and a half gallons of water per minute. This means that a ten-minute shower will use up to twenty-five gallons of water
A bathtub typically holds between thirty and one hundred gallons of water. This means that a typical bath will use more water than a typical shower.
A low flow shower head can reduce the water usage even further.
Bottom Line — How Many Gallons Does A Bathtub Hold?
When it comes to how many gallons a bathtub can hold, there is no one definitive answer. The amount of water that a tub can hold depends on its size and shape, as well as how much the person using it intends to fill it up. However, most standard bathroom tubs can generally hold between 40 and 60 gallons of water before overflowing.