How much does it cost to add a bathroom?

Experts reveal the costs of adding a bathroom to make life at home run more smoothly

Cost to add a bathroom: White shared bathroom with white marble walls and brass details
(Image credit: Barlow & Barlow)

Asking, how much does it cost to add a bathroom? Whether there are too many family members lining up to use the shower at the same time, or you want to give guests their own dedicated bathroom, an extra can be a huge boon.

Of course, you might equally want to add a bathroom to make your own part of the house more comfortable with a luxury design accessible from the primary bedroom, or perhaps add a powder room convenient for visitors as well as family.

Whatever your goals, it’s important to know the cost to add a bathroom so you can plan your budget and we’ve asked an expert to explain the options and how much you can expect to pay.

How much does it cost to add a bathroom?

There are many elements that will influence the cost to add a bathroom to your home. These include its size and the type of bathroom.

Bear in mind, too that it will doubtless cost more to add a bathroom than a simple bathroom remodel cost. Also crucial is whether you are converting existing space or planning an addition to make space for the bathroom. 

‘In the first case, you can expect costs that are similar to a brand-new, full bathroom remodel where the room is taken down to the studs,’ explains Cristina Miguelez, remodeling specialist for Fixr. ‘A full-sized bathroom that is added to an existing space will typically cost between $7,000 and $12,500 on average. 

‘Building an addition to house the bathroom will be more expensive, ranging between $14,000 to $30,000 on average,’ she explains.

Cost to add a bathroom by type

A bathroom could be anything from a powder room that’s a half bath with toilet and sink to a large primary bathroom with space for tub, shower and double vanity.

But it is not just the room’s fittings and size that dictate what you can expect to pay; the costs will vary according to whether it is located in an existing space or part of a new addition.

Cristina offers the following guide to costs.

Powder room with toilet and sink. Existing space: $3,000 to $5,000. Building a new addition: $8,000 to $12,000

Three-quarter bathroom with sink, toilet and shower. Existing space: $5,000 to $7,500. Building a new addition: $10,000 to $18,000

Full bathroom with sink, toilet, shower and full tub. Existing space: $7,000 to $12,500. Building a new addition: $14,000 to $30,000

Guest bathroom Existing space: $7,000 to $12,500. Building a new addition: $14,000 to $30,000

Master bathroom with toilet, double vanity, shower and tub. Existing space: $20,000 to $40,000. Building a new addition: $40,000 to $96,000

The effect of location on the cost to add a bathroom

Where you locate it influences the cost of adding a bathroom to your home, so factor this into your budget calculations.

‘One rule of thumb is that the further your new bathroom is from the finished areas of your home, the more it will cost you,’ advises Cristina.

‘If you are converting an existing space, the more finished the space is, the less expensive it will be to turn it into a bathroom. For example, adding a bathroom to an unfinished basement will cost you nearly as much as an addition (that includes the foundation or crawl space extension, framing, etc). 

‘Adding a bathroom to a tiled area with plumbing nearby will lower the costs, getting them closer to a bathroom remodel.’

Other factors which influence bathroom cost

There are other aspects that determine the final cost to add a bathroom.

‘The size and scope of the project are two factors that affect cost the most,’ says Cristina. ‘The larger the bathroom and the more features you want to include, the more expensive it will be.

Plumbing, directly related to location, is essential as well. Adding or modifying new plumbing can be a significant part of the overall cost. Adding a bathroom next to a space with nearby plumbing will be much less expensive than adding a bathroom in an isolated area of the house.

‘The cost of fixtures can have a significant impact, too. A two-piece toilet can cost $300, while a wall-hung one will cost around $1,000. There are also many types and sizes of sinks and cabinets that can increase the cost. Whether you install a shower, a bathtub, or both can influence the price you end up paying, too. In general, installing a shower is cheaper than a tub, but you can end up paying $10,000 plus for exotic bathtubs with jets requiring complex installation.

‘The materials and finishes you decide to use for walls and flooring will also impact the cost. For example, it can vary significantly if you opt for natural stone tiles instead of ceramic or porcelain tiles. This can increase even the maintenance costs, as some natural materials are more expensive and difficult to maintain.' 

You can discover more about bathroom flooring installation costs and bathroom tile costs in our dedicated features.

‘Finally, the labor costs can vary greatly depending on where you live and the project’s complexity. Local regulations will also dictate permits and inspections.’

While not a necessity, you might consider using universal design in your bathroom to make aging in place easier, Cristina suggests. ‘Doing so may also open your home to a broader market at resale time and make your home accessible for any type of user,’ she says.

Is adding a bathroom worth it?

Often, adding a bathroom is worth it. ‘The average ROI of adding a bathroom (mid range) is 51.8 per cent,’ says Cristina Miguelez, remodeling specialist for Fixr

‘Of course, this will change depending on where you live and the current characteristics of your home. For example, if you have a three or four-bedroom house with only one bathroom, adding a second one can increase your chances of selling your house. On the other hand, if your home has two bathrooms for two bedrooms, the ROI of adding a third bathroom won’t be as good.’

Can I put a bathroom anywhere in my house?

Technically, you can put a bathroom anywhere in your house, according to Cristina Miguelez, remodeling specialist for Fixr. ‘However, it will depend on your current plumbing and electrical systems, as you will need to run a waste pipe for each toilet, which limits the options,’ she explains. ‘This will be key in determining how cost-effective your project will be and how difficult it can get.’

Call in a pro to talk over your options and their cost implications.

Sarah Warwick
Contributing Editor

Sarah is a freelance journalist and editor. Previously executive editor of Ideal Home, she’s specialized in interiors, property and gardens for over 20 years, and covers interior design, house design, gardens, and cleaning and organizing a home for H&G. She’s written for websites, including Houzz, Channel 4’s flagship website, 4Homes, and Future’s T3; national newspapers, including The Guardian; and magazines including Future’s Country Homes & Interiors, Homebuilding & Renovating, Period Living, and Style at Home, as well as House Beautiful, Good Homes, Grand Designs, Homes & Antiques, LandLove and The English Home among others. It’s no big surprise that she likes to put what she writes about into practice, and is a serial house renovator.