How to Measure Soaking Depth of Tub

Knowing the right soaking depth of the tub is crucial if you want a comfortable bathing experience. The ideal soaking depth of a tub is roughly 14 to 15 inches.

Some homeowners prefer lower while others prefer higher soaking depths. Additionally, the depth will eventually be determined by the size of the tub.

But it is important that the water level in the tub does not cause any risks. Particularly if you have young children in the house.

To determine the soaking depth of the tub, you will need to understand a few things. Preference, safety, and standard code.

In this article, you’ll know how to measure the soaking depth of a tub as well as the standard soaking depth tub.

What is Soaking Depth of Bathtub?

If you have a bathtub installed at home, you should know the precise depth of water for comfortable baths or hydrotherapy.

The depth of water, however, is different for every individual. This is called soaking depth. You can also define soaking depth as the amount of water contained in a tub to cover the user’s body (75% or 80%).

According to the standard codes, the soaking depth of a bathtub is between 14 to 15 inches.

But if the tub is small, you can have 12-inches of soaking depth. Any excess water will drain when the soaking depth is exceeded.

How to Measure Soaking Depth of Tub

You do not require sophisticated tools and requirements to measure the soaking depth of a tub.

Step 1: Roughly Checking the Tub’s Dimension

The depth of a tub should be determined by the overall dimension of the tub. From its length, width, height, and basin size.

The length and width of a small tub, for instance, should have a shallow soaking depth if the tub holds less than 30 gallons of water.

So, check the dimensions either in inches or feet using a tape measure or any other similar measuring tool.

Step 2: Measuring the Length, Width, Depth, and Height

It is easy to get the dimensions of your tub with a tape measure.

For the height, place your tape measure on the floor and measure the height from the floor to the top of the tub.

Make sure that the tape is standing at a 90-degree angle. The height of the bathtub should, however, not be measured from the base of the tub.

For the length, place your tape measure on the outside wall of the front side (head) to the outside wall of the other side (leg).

Note that you should place the tape measure at the longest point for a curved bathtub.

For the width, place your tape to measure the outside edge of the right side to the outside edge of the left side.

For the depth, which is our primary focus, you should place your tape measure on the interior floor of the bathtub of the overflow hole/allowance. Do not measure the tub from the inside.

Step 3: Measuring and Determining the Soaking Depth

The soaking depth can determine how comfortable you will feel while taking a bath.

Ordinarily, the standard soaking depth is 14-inches which is according to the standard bathtub codes.

But you need to understand that the soaking depth will always be determined by how you want to feel while taking a bath or even relaxing inside the tub.

You will have an idea of the soaking depth after you have the correct length, height, and width reading.

These dimensions will help you know how much water volume the tub can hold.

Note that if the tub has a shallow overflow hole, then the soaking depth will not be equal to a tub with a higher overflow hole.

Step 4: Determining the Volume of Water in a Tub

Once you know how much volume the tub can hold, you need to calculate how much space you would occupy in the tub. The amount of space occupied will help you determine the soaking depth.

A standard bathtub should hold approximately 42 gallons (159 liters) of water up to the overflow allowance. However, some of the water will be displaced when a body is inserted into the tub.

Therefore, a wider body mass will displace more water than a narrow body mass. For a narrow body, the tub will hold more water than a wider body.

Also Read: How to Install a Bathtub on a Concrete Floor

What is the Difference between a Soaking Air Tub and Regular Tub?

Most old-fashioned homes have regular tubs fitted inside the bathroom. But nowadays, the design and layout of bathrooms have changed and homes are now built with soaking air tubs.

These two fixtures are similar in a slight way but different in another. So, what is the difference between the two?

The major difference between the two is functionality. Other differences are, however, present as well.

Soaking air tubs have a pump installed whereas a regular bathtub does not have a pump or any other mechanism to blow hot or cold air.

Here are four other significant differences that you should understand.

Soaking Air Tub

  • A soaking air tub, just as the name suggests, is a tub with jets that produce air from an air pump to create a sensational feeling to your skin.
  • Soaking tubs are generally deeper than regular tubs.
  • Soaking air tubs can hold up to 250 gallons of water.
  • The average size of a soaking tub is 23-inches high.

Also Read: Air Tub vs Whirlpool Tub – What’s The Main Difference?

Regular Tub

  • A regular or ordinary tub is an oval or round-shaped basin that has a drain and its common purpose is to take warm or hot baths. You will, however, never find jets of water in a regular tub.
  • An ordinary tub is not as deep as a soaking air tub.
  • A regular tub can hold up to 50 gallons of water. Other customized designs, though, can hold more water.
  • The average size of a soaking tub is 19-inches high.

Related Helpful Resource:


The ideal soaking depth according to standard bathtub codes is either 14 or 15-inches. But with the above insight, the soaking depth of a tub should be measured by your preferences.

Some users can prefer a shallow depth while others a higher depth up to the overflow hole.

For small tubs with limited space in the bathroom, for instance, the soaking depth cannot be the same as a large tub with higher dimensions or measurements.

Smaller tubs, for example, will have a shallow soaking depth than the large bathtubs.

Therefore, use a tape measure correctly to know the correct soaking depth measurement.

This guide has looked at how to measure the soaking depth of the tub as well as the ideal soaking depth of the bathtub.