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How Big Should A Bathroom Be? | Sizes & Dimensions

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How Big Should A Bathroom Be?
A contemporary design for a large bathroom – Image courtesy of Maya’s Design Studio

When designing a bathroom, size is one of the most important factors to consider. Size can significantly impact the functionality and comfort of your space.

Maya Mogdahan

In this article, we’ll discuss how to measure everything in your bathroom for problem-free planning. However, keep in mind the advice of Maya Moghadam, Owner of Maya’s Design Studio: 

“As a designer, I recommend having a professional contractor measure all the unique requirements. They know how to measure correctly so that you don’t waste your money or time.” 

Maya and her team can recommend a contractor, create an e-design, and shop with you to help turn your bathroom into a haven in your home.

Maya’s Design Studio offers virtual services all over the world. To get an extended free consultation on your bathroom design or remodel, and advice on measuring, click the button below and be sure to mention that you came from Bathtubber:

So, how big should a bathroom be? The answer to this design question will vary depending on a few key factors. Read on to find out what these are and what you need to know about bathroom sizes.

If you are planning a complete remodel of your bathroom and need to measure all your bathroom fittings and available space, take a look at our guide on How to Measure EVERYTHING in Your Bathroom.

Minimum Bathroom Sizes

Measure Thickness of Bathroom Tiles

Are you designing or remodeling a bathroom? Below is a quick reference guide to minimum average bathroom sizes:

Type of BathroomAverage Size
Standard Bathroom40 square feet (3.7 sq meters)Intended as a general family bathroom to cater to 2 to 4 people.
Master or Primary Bathroom100 square feet (9.29 sq meters)A larger, more luxurious bathroom space for the homeowners or the occupants of the master bedroom. Caters to 2 people.
Guest Bathroom30 square feet (2.78 sq meters) to 36 square feet (3.34 sq meters)A reduced version of a standard bathroom, often with a toilet, vanity, and either a bath or a shower.
Half Bath Or Powder Room18 square feet (1.67 sq meters) to 20 square feet (1.85 sq meters)A basic bathroom for guests, which includes a toilet and a sink.
ADA Bathroom23 square feet (2.13 sq meters)

The 40 square feet minimum does not apply to private residences.
A bathroom that maximizes central space. Fixtures that maximize toe and knee space are selected, and with no steps to access the shower. Handles, sinks, and faucets are also installed at heights suitable for use from a wheelchair.

Are All Bathrooms Standard Sizes?

Down Sconce Above Mirror

Bathrooms come in various sizes, and not all are of standard dimensions. Standard sizes are determined based on the average dimensions of fixtures and fittings, and these sizes can vary depending on the country or region.

Bathrooms of different sizes are generally given names that indicate the size and available features of the bathroom. Besides full bathrooms, there are half baths, also known as powder rooms, and guest baths.

How Big Is A Standard Bathroom?

Shower Border Accent Tile in Bathroom

A standard bathroom typically has an area of around 40 square feet (3.71 sq meters), with dimensions of 5 feet by 8 feet (1.52 meters by 2.43 meters). 

This size allows for the installation of essential fixtures, such as a sink, toilet, shower, and bathtub.

The minimum ceiling height for a standard bathroom, as stipulated by the International Residential Code (IRC), is 6 feet (1.82 meters) to ensure adequate headroom for showering and bathing. 

However, a higher ceiling can create a greater sense of spaciousness, as well as improve ventilation.

Consult the IRC along with your local building codes for additional local recommendations and restrictions.

How Big Is An Average Master Bath?

How big should a bathroom be
Double vanity concept for a bathroom – Image courtesy of Maya’s Design Studio.

To get an extended FREE consultation on your bathroom design or remodel, and advice on measuring, click the button below. Be sure to mention that you came from Bathtubber.

An average master or primary bathroom is typically larger than a standard bathroom, with an area of around 100 square feet (9.29 sq meters) or more. 

The extra space allows for the inclusion of additional features, such as a double vanity, a separate shower and bathtub, and more storage.

The ceiling height of a master bathroom is typically the same as a standard bathroom, with a minimum height of 6 feet (1.82 meters). 

However, most homeowners may choose to have higher ceilings of at least 7 feet (2.13 meters) to create additional headroom and a sense of spaciousness.

Common Fixtures in a Primary Bath

Personal preferences and available space usually determine the layout of a master (aka “primary”) bathroom. Some common fixtures of a master bathroom include:

Double Vanity

A double vanity is popular in master bathrooms, providing two sinks and ample counter space. The average width of a double vanity is around 60 inches (152.4 cm).

Separate shower and bathtub. 

Many homeowners prefer to have a separate shower and bathtub in their master bathroom. The average size of a shower stall is around 36 inches (91.4 cm) by 36 inches (91.4 cm), while the average size of a bathtub is around 60 inches (152.4 cm) by 30 inches (76.2 cm).


Master bathrooms often include additional storage, such as built-in cabinets, linen closets, or a separate room for a toilet.

Additional features

Some homeowners opt to include additional luxury features in their primary bathroom, such as a bidet, a smart shower, or a soaking tub.

How Big Is A Guest Bathroom?

Bathroom Tile Thickness

Guest bathrooms are typically smaller than full bathrooms but larger than half baths. 

For this reason, guest bathrooms are often called three-quarter bathrooms, although they may not be exactly 75% of a full bathroom. 

They are designed to accommodate visitors and may have additional features such as a shower or bidet.

The average size of a guest bathroom is generally between 30 square feet (2.78 sq meters) and 36 square feet (3.34 sq meters), which is only slightly smaller than a standard bathroom.

The available space and the desired features often determine the layout of a guest bathroom. A guest bathroom layout usually includes a sink, toilet, and shower but no bathtub.

A guest bathroom typically has more storage space than a powder room or half bathroom in order to give guests space to pack out their toiletries for the duration of their stay.

How Big Is A Half Bathroom Or Powder Room?

Vinyl Tile is Great for Rental Properties

Half baths usually contain only a toilet and a sink and are typically smaller than full bathrooms and guest bathrooms, with an area of around 20 square feet (1.85 sq meters).

It is usually located near the main living areas of a home, such as the living room or dining room, and is intended for guest use.

The average half-bath size is around 20 square feet (1.85 sq meters) but can be as small as 18 square feet (1.67 sq meters).

The available space and the location of the plumbing often determine the layout of a half bath. Some popular layouts for a half bath include:

Sink and toilet on the same wall

This layout is the most common for a half bath and is ideal for narrow spaces. The sink and toilet are typically placed side-by-side on the same wall.

Sink and toilet on opposite walls

This layout is ideal for wider spaces and provides more room for movement. The sink and toilet are placed on opposite walls, with a space in between.

Corner sink and toilet 

This layout is ideal for small spaces and provides more room for movement. The sink and toilet are placed in opposite corners, with a space in between.

ADA Bathroom Size Requirements

Interior of modern toilet with handrail

ADA (Americans with Disabilities Act) bathroom size requirements are guidelines for designing accessible bathrooms suitable for people with disabilities. These guidelines aim to ensure that people with disabilities have equal access to bathrooms and can use them comfortably and safely.

The minimum ADA bathroom size requirements are as follows:

Bathroom Door Width

The minimum bathroom door width for an accessible bathroom is 32 inches (81.28 cm), with a clear opening width of 31.5 inches (80.00 cm).

Maneuvering Space

There should be enough space in the bathroom for a wheelchair to maneuver comfortably. The minimum clear floor space required in front of a toilet or sink is 30 inches (76.20 cm) by 48 inches (121.92 cm).

Toilet Height 

The required toilet seat height must be between 17 and 19 inches (43.18 and 48.26 cm) above the floor.

Grab Bars

Grab bars must be installed in specific locations to provide support and stability for people with disabilities. They should be at least 1.25 inches (3.17 cm) in diameter and have a smooth surface. The grab bars should be mounted at a height between 33 and 36 inches (83.82 and 91.44 cm) above the floor.

Sink Height

The sink should have a rim height of no more than 34 inches (86.36 cm) above the floor. The bottom of the sink should be no higher than 29 inches (73.66 cm) above the floor.

Shower Size

The minimum clear floor space in a shower is 36 inches (91.44 cm) by 36 inches (91.44 cm). A roll-in shower should have a clear floor space of at least 60 inches (152.40 cm) by 30 inches (76.20 cm).

Shower Bench

A shower bench must be provided in a roll-in shower. The bench should be at least 24 inches (60.96 cm) wide and 15 inches (38.10 cm) deep.

ADA Minimum Requirements

How to measure bathroom tile thickness

It is important for homeowners to note that these are only minimum requirements, and designers and architects are encouraged to exceed these standards whenever possible to improve accessibility and comfort for people with disabilities.

With these minimum space requirements, the average ADA bathroom should be 23.3 square feet (2.16 sq meters). 

ADA bathrooms in commercial properties must be a minimum of 40 square feet (3.71sq meters), but this regulation does not apply to private residences.

Designers and architects are encouraged to exceed these standards whenever possible to improve accessibility and comfort for people with disabilities.

How to Determine Your Ideal Bathroom Size

How big should a bathroom be
Order this look from Maya’s Design Studio – Say you saw it on Bathtubber and loved it!

We are all different with specific needs and requirements for our bathrooms. Whether you need a small bathroom or a large one, with or without a bathtub or a shower, there are questions that can be helpful to answer before you decide on the right size bathroom for you.

The Available Space 

If you are remodeling your existing bathroom and adding a new bathroom, the size of the new room will be determined by the space available on your property.

You can be more generous with your fixtures and fittings if you have a large, spacious bathroom. If your bathroom space is on the smaller side, you will need to be a bit more creative with your use of the space.

The Number Of Users

Designing the space around the number of users is a great idea. For example, you will need a larger bathroom for a family of four than a single-person home. A bathtub with a separate toilet area might be necessary for a family with children.

Or, if you only have a single bathroom for multiple users, a shower, vanity, and toilet might suit the space better.

Remodeling for Resale

If you are remodeling with the intent to sell your home, stick to basic designs. An added bathroom can greatly increase the value of your home. According to a National Association of Housing Builders (NAHB) model, bathrooms can add 10% to 20% more value to your home. Yet, this all depends on the type of bathroom and its amenities.

Consider your future needs when planning a new bathroom or a bathroom remodel. Will your family be growing in size, or will you be aging in place? Incorporating features like a walk-in shower or grab bars can help make your bathroom safe and comfortable into your twilight years!

Remodeling to Rent

If you are remodeling a house to use as a rental property, consider the most durable tile and fixtures, as they will need to last.

Your Budget

Your budget is a very important factor when determining the size of your bathroom. A larger budget could mean a bigger space with more high-end fixtures and fittings, which could take up more space.

If your budget is tighter, you might have to compromise on bathroom size to keep costs down. Either way, cost-efficient and eco-friendly fixtures and fittings are available to help you reduce running costs.

And if you want to save on an expensive bathroom remodel, keep fixtures on the existing plumbing wall.

So How Big Should a Bathroom Be?

large format tile on small bathroom floor

There are no one-size-fits-all answers to how big a bathroom should be. The ideal size of a bathroom depends on several factors, such as the room’s available space, functionality, storage, accessibility, style, number of people, and future needs.

Smaller bathrooms have limited room to add additional features and comforts and generally only cater to the basics. Standard sizes of fittings and fixtures will be a limiting factor in how small your bathroom can be.

For more help with sizing in a bathroom remodel, see our complete bathroom vanity size guide, bathroom sink size guide, bathroom mirror size guidetile size guide, bathtub size guide, and standard shower size guide.

Note: Would you like designer hacks that can literally save you thousands of dollars on a bathroom remodel? Just fill out the form below and I’ll send the Save Big $$$ Cheat Sheet straight to your inbox.

Tags: average master bath size, bathroom size, how big is a half bath, ideal bathroom size, size of guest bathroom, standard bathroom size

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