Search thousands of topics on

BROWSE ALL TOPICS >> appliances babies & children  cars  consumer electronics health & personal care home & garden personal finance  pets  schools small business weddings
CostHelper > Home and Garden  > Construction & Renovation > Bathroom Addition

Bathroom Addition Cost

How Much Does a Bathroom Addition Cost?

low costLow: DIY Materials Start $500-$1,500average costMedium: Simple Conversion Starts $3,000-$6,000high costHigh: Adding Floor space Can Run $25,000-$50,000+
post E-mail post Post   Comments (4)

A bathroom addition can range from a small half-bath (sink, toilet and mirror) to a spa-like master bath. Adding a bathroom is usually more expensive per square foot than other rooms because it requires specific types of plumbing, heating, electricity and ventilation.

Typical costs:

  • Converting existing floor space inside a garage, basement or attic into a simple bathroom starts around $3,000-$6,000. However, costs can be $7,000-$25,000 or more for a more luxurious bathroom, or if the new bathroom is far from existing water and sewer lines. Prices may vary significantly by region, depending on local labor rates.
  • Costs for do-it-yourself materials start around $500-$1,500, but can run $2,000-$5,000 or more depending on room size, the quality of fixtures and other amenities. A Pennsylvania homeowner[1] added a 4x8-foot powder room with granite and upgraded fixtures for about $5,000, doing all the work himself except the rough-in plumbing.
  • Adding new floor space to your home for a basic 6x8-foot bathroom addition starts around $25,000-$50,000 and goes up depending on complexity, quality of fixtures, number of amenities and local labor rates. Remodeling Magazine[2] pegs the price of a 6x8-foot bathroom addition at averages of $33,188-$41,195 in the Midwest, $34,876-$42,491 along the East Coast and $35,987-$47,052 in the Western states. For a spa-quality 100-square-foot master bath the survey says it averages $75,812 nationwide.
Related articles: Home Addition, Bedroom Addition, Family Room Addition, Second Floor Addition, Porch, Basement Remodeling

What should be included:
  • If you're adding new floor space, before you do anything else check with your local planning department. Better Homes and Gardens provides an overview of legal remodeling requirements.
  • As a general rule, a half-bath should be at least 3-4 feet wide and 6-8 feet long, or at least 18 square feet; a bathroom with shower should be 30 square feet or more; and a bath with both a shower and tub should be at least 35 square feet. explains how to plan a half-bath[3] (also called a bonus bath) while lists things to consider[4] for any size bathroom addition.
Additional costs:
  • Adding a tile floor, marble counter tops, or other upscale features can dramatically increase the weight load on your foundation. You might need to consult with a structural engineer (anywhere from $300-$800 or more, depending on what's needed and rates in your area) to see if the foundation needs to be reinforced.
  • Hiring an architect to create a set of plan drawings could cost you a flat fee of $700-$30,000 or more, depending on size and complexity, or the architect may charge 5-15 percent of the project's costs.
  • Usually a bathroom addition will trigger a reassessment of your property taxes and a resulting tax increase, but in most areas the reassessment will only be on the value of the addition, not the entire house.
  • Bathroom design books[5] cost $10-$40 or more, and can give you great ideas and tips; they may also be available at your local library.
Shopping for a bathroom addition:
  • Gather photos of bathroom styles and details that appeal to you. Better Homes and Gardens displays a slide show of contemporary styles and Kasmar Publications posts pictures of luxury bathrooms.
  • Even if you want to do some of the work yourself, most experts recommend hiring a licensed and certified plumber. Ask family or friends for recommendations, or search for referrals from the Plumbing-Heating-Cooling Contractors Association[6] and the National Electrical Contractors Association[7] .
  • If you want a remodeling contractor to handle all aspects of your bathroom addition, the National Association for the Remodeling Industry provides an online booklet with tips[8] for hiring a contractors, as well as contractor referrals[9] .
  • Check whether a contractor is licensed[10] in your state, and if there are any complaints with the Better Business Bureau[11] . A written contract should include a detailed outline of the work required and materials used, dates within which the project will be done, and a payment schedule.
post E-mail post Post   Comments (4)
CostHelper News

7 Lesser-Known Discounts for the 50+ Crowd
As they age, members of the Baby Boomer generation don't like to admit that they're senior citizens, but they love getting discounts. It's kind of a quandary, because some of the best deals available are reduced prices for older folks. || Posted October 21 2013

Our Top 10 Favorite Secret Menu Items
Don't believe everything you read. Those menus posted at your favorite fast food spot or coffee stand are not the be all and end all of their offerings. || Posted October 25 2013

‣ All CostHelper Blog Posts

What People Are Paying - Recent Comments
Adding a full bath to basement
Amount: $9,000.00 total
Posted by: a user in Timonium, MD.Posted: January 27th, 2015 07:01PM
Square Feet: 36Contractor: Self
Required adding all plumbing and electrical work. Also adding an exhaust fan that required drilling a 6-in hole through exterior brick wall of house. Used high-end building materials: cast iron shower pan, glass frameless shower door, ceramic wall tile with custom niche for soap, marble counter top, slate flooring, and high-end fixtures/faucets.
Was this post helpful to you?   yes     no Report prohibited or spam
Bathroom Addition Costs
Amount: $4,300.00 total
Posted by: Frick in Madeira Beach, FL.Posted: December 28th, 2013 07:12AM
Square Feet: 52Contractor: Self
Built a full bath in the "Florida basement" space from the garage area of my three story home. Building out masonry walls, tapping into the sewer and water, running electrical, fitting out a two head shower, tiled walls and floor, and AC ducts.
Was this post helpful to you?   yes     no Report prohibited or spam
Would like to add upstairs bath - What is the cost???
Amount: $5,000.00 total
Posted by: JT in Minneapolis, MN.Posted: April 26th, 2012 09:04AM
Square Feet: Approx. 40Contractor: Self and outside
I would like to get and estimate of how much it would cost to add a master bath to the upstairs of my 1.5 story house. Using existing floorspace, framining myself and installing pre-fab vanities, sinks and showers. Hiring for outside plumbing. Bathroom would be about 10-15 feet from existing plumbing a floor below. Any thoughts on how much this will run me???
Was this post helpful to you?   yes     no Report prohibited or spam
Add (1) full bath and remodel (1) 1/2-bath
Amount: $6,000.00 total
Posted by: C. T. in Indianapolis, IN.Posted: August 1st, 2009 07:08PM
Square Feet: 120Contractor: self
To break concrete floor and install drainage and vents I hired a plumbing company, which was $4500. I did the remainder of work including electrical and other.
Was this post helpful to you?   yes     no Report prohibited or spam


Comment On Your Experience With a Bathroom Addition
Subject:  *
Amount Spent:  * total
Square Feet: Contractor: 
Purchased:  Year: 
City:  * State:  *
Information about you:
Email:  * Email addresses are not displayed.
Name:  This is the name we'll display with your post.
me on this computer
*=required field.

External Resources:
More Home and Garden Topics
Check Out All Costs for Home and Garden How Much Does Garden Service Cost? How Much Does a Kitchen Remodeling Cost? How Much Does a Propane Tank Cost?

Search Thousands of Topics on


Today's Featured Cost Articles

About CostHelper
CostHelper is based in Silicon Valley and provides consumers with unbiased price information about thousands of goods and services. Our writers are experienced journalists who adhere to our strict editorial ethics policy.

CostHelper Community
Angiogram of heart
Paid: 55150.00
Had this procedure done to check heart due to abnormal stress test. Did not need any stents or any other procedure as everything was negative... [more]
-Pamela Garrett
Angiogram Cost
HELP: asbestos in furance - many questions
Paid: 0.00
I am renting out my home in Grand Rapids, MI and have received a notice from the city that the home must be inspected... [more]
Asbestos Removal Cost
Paid: 45.00
The clamp was annoying so it took away concentration of the tiny sting of the needle. I had just turned 15 at the the time and I've had it for almost a year and it has healed fast and never given me any trouble... [more]
Body Piercings Cost
Paid: 3009.00
Single family home... [more]
Ductwork Cost
2 half shafts replaced
Paid: 140.00
Bought the axles myself on ebay for 40 each, then had a mobile mechanic come to my house to do the work. It is not a hard job, but has a couple tricky parts for a subaru. Easier for a honda or toyota... [more]
-Subbie Giy
Replacing a CV Boot Cost
Even with insurance looking at going broke
Paid: 55000.00
Recently on a camping vacation my 11 year old became very sick. Took him to the closest hospital. Found out he is type 1 diabetic. Was very sick and had to be flown from Rock Springs WY, to Salt Lake City, UT. 185 mile on the ground... [more]
-Broke and confused.
Air Ambulance Cost