How Much Does It Cost to Add a Bathroom in St. Louis, MO? [2026 Data]

St. Louis, MO’s lower cost of living keeps bathroom addition costs below the national average. The average cost to add a bathroom in St. Louis, MO, is $33,285, with most projects ranging from $4,755 to $71,325. Below, we’ll explore how factors like your project size, material choices, and local labor rates impact your total so you can budget accordingly.

Bathroom Addition Cost Factors 

When budgeting for a bathroom addition in St. Louis, MO, you’ll need to factor in your bathroom size, type, and location. Your chosen features, appliances, and materials will also impact your total.

Type of Bathroom 

You’ll want to plan the type of bathroom addition based on its location in your home and your budget. Full and primary bathrooms are more common in primary bedrooms and on the second floor, while you might opt for a half bath in a first-floor guest bathroom. 

Here’s a breakdown of the average costs to add different types of bathrooms:

• Half bath: A half bath has two of four major bathroom fixtures (typically a sink and toilet), and ranges from $3,800 to $11,400 for a 15- to 25-square-foot space. You could spend as little as $2,900 for a basic conversion or as much as $14,300 for a brand-new powder room with designer fixtures.

• Three-quarter bathroom: Expect to pay $5,700 to $20,900 to add a three-quarter bathroom that’s around 25 to 40 square feet. This bathroom has a toilet, sink, and shower. You could spend as little as $3,800 if there’s existing plumbing or as much as $23,800 for a luxury bathroom addition.

• Full bathroom: A full bathroom costs $9,500 to $47,600, ranges from 40 to 100 square feet, and has a sink, toilet, shower, and bathtub. Larger layouts include a built-in cabinet or linen closet.

• Primary bathroom: A primary bathroom addition costs $20,900 to $85,600 and connects to the primary bedroom. You can spend as little as $14,300 on a basic conversion or more than $95,100 on high-end fixtures like a freestanding tub and a luxury walk-in shower.

• Jack and Jill bathroom: A Jack and Jill bathroom costs $23,800 to $95,100, depending on the fixtures and scale. These bathrooms connect two bedrooms or one bedroom to a hallway. Depending on the design, they measure 100 to 200 square feet and often have two sinks and an enclosed toilet. 

• Wet room: The average cost to add a wet room is $5,700 to $19,000, but you could spend up to $28,500 on a luxury design. Wet rooms are about the same size as a three-quarter bathroom, but costs can run higher for waterproofing the entire space and grading for drainage. 

Bathroom Size

Your bathroom’s square footage majorly influences the cost. A bathroom conversion costs $190 to $240 per square foot, whereas a bathroom addition costs $380 to $520 per square foot. 

Here’s a breakdown of the estimated costs to add a bathroom based on size:

Bathroom Location

Where you build a new bathroom will impact its final cost. Here are the average prices to add a bathroom, based on its location in your home. 

Features and Fixtures

If you want your bathroom to have premium features, you'll pay extra. A jetted tub can cost around $9,500, for example, and bathroom vanities can cost anywhere from $480 to $3,800. 

We cover different bathroom features below so you know how much to budget for your specific project:

Materials

Materials make up about 45% of the total project cost, so the choices you make will be significant. A bathroom addition built with midrange materials costs an average of $56,100, while an upscale bathroom addition costs an average of $102,200. 

Here are some of the major cost considerations based on material quality to keep in mind:

• Luxury materials: Luxury materials can help you emulate the feel of a bathroom at a five-star hotel and last longer, but expect to pay more for spa-like features. Research the maintenance needs for materials like marble, which require more effort to clean. 

• Midrange: Midrange materials are the most popular choice for St. Louis, MO, homeowners, offering a balance between durability and affordability. They come in a wide range of styles, offering a refined look without the premium price tag.  

• Budget materials: Budget materials can help you save while still bringing your vision to life. Many cost-effective surfaces, like tile, are easier to clean than luxury alternatives. However, remember that the lowest-end materials aren’t as durable.

Bathroom Remodeling Pro Costs

Labor accounts for 40% to 65% of your bathroom addition project in St. Louis, MO. When budgeting for hiring a bathroom remodeler in St. Louis, MO, you’ll need to consider local crew rates, permit fees, and any additional pros. 

Labor 

Bathroom remodelers in St. Louis, MO, charge an average of $50 to $100 per hour. Your total labor costs will depend on the size and complexity of your project, with primary or Jack and Jill bathrooms requiring more crew time than a simple half bath.

When comparing quotes, confirm that your pro has the proper licensing and insurance. While not necessary, you can also provide a tip once the project is complete if the crew went above and beyond.

Permits

Permits are required for most bathroom additions in St. Louis, MO. If your project involves plumbing, electrical, or structural changes, budget an additional $200 to $500 for permits and inspections. Your contractor will often pull the permits and coordinate inspections for you, so confirm that those costs are included in your quote.

Additional Pros to Consider Hiring 

Remodeling or building a bathroom is a big job, and bathroom remodelers often subcontract parts of the work to other pros, including:

• Plumbing: Plumbing is a significant cost when adding a bathroom. The farther your new bathroom is from existing plumbing, the more it will cost. Plus, you might need a new septic tank, depending on its current capacity and local requirements. On average, expect plumbing to cost $950 to $9,500.

• Electrical: The cost of getting your electrical in place varies based on whether you’re using existing wiring or if your pro will need to install everything themselves. Electrical work for a new bathroom can cost $480 to $2,400. 

• General contractor: Some larger projects may require a general contractor to coordinate permits, scheduling, and trades. These pros charge 10% to 20% of the total project cost.

Does Adding a Bathroom Increase Home Value?

Adding a bathroom offers a potential 30% to 50% return on investment (ROI) for St. Louis, MO, homeowners. The city’s older bungalows and historic homes were often built with just one bathroom, so a well-placed addition can help your home stand out on the market and attract more buyers. Having an additional bathroom also offers added convenience, functionality, and aesthetics to your home, offering long-term value for your household and future resale potential.

How Angi Gets Its Local Cost Data 

To help homeowners plan their next project, Angi provides readers with carefully researched cost data and upholds strict editorial standards. We start with national average project costs, which we collect by analyzing competitor information, retailer material costs, and input from professional contractors. We then apply local price index data to calculate location-specific estimates that reflect what homeowners typically pay in their local area. To do that, we use data from the U.S. Bureau of Economic Analysis (BEA), including its Regional Price Parities (RPPs), which measure price differences across cities. This helps us account for differences in labor, materials, and overall cost of living, so estimates in higher- or lower-cost areas better reflect real-world local pricing.

Every estimate undergoes a thorough editorial review to verify accuracy, consistency, and alignment with observed market conditions.

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