How Much Does a Home Addition Cost?

Learn about the expenses involved in home additions

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Many people turn to home additions to create larger living spaces or add rooms they need, from sunrooms to extra bedrooms. These major projects are often more affordable than buying a new home with the same features, but they are also a major expense, easily costing thousands of dollars.

Learn more about expenses to consider when you estimate the cost of your home addition so you can plan for it in your budget.

Home Addition Cost Estimates

The cost of a home addition can vary depending on a lot of different factors. You might spend $10,000, $100,000, or anywhere in between.

Here are common factors that affect the cost of a home addition:

  • Type of addition: Some rooms are more complex than others. A bedroom doesn't require as much infrastructure as an in-law suite, for example. The more complicated a room, the more expensive it costs.
  • Materials used: The cost of construction materials such as lumber and features like spa tubs or kitchen appliances can affect the price of an addition.
  • Contractor: You may get a wide range of estimates from different contractors for the same project.
  • Square footage: The bigger the addition, the more it will cost, all other factors being equal.
  • Location: Construction costs may be higher where the cost of living is higher, such as in metropolitan areas.
  • Up versus out: Building an addition above the ground floor is more challenging for builders, so a first-floor addition is generally less expensive than a second-floor addition. In other words, it is cheaper to build out than to build up.
  • Economic conditions: Broader economic trends play a role in home addition costs. For example, a tight labor pool can cause a shortage of construction workers, which in turn could result in builders paying higher wages to try to fill positions. Ultimately, in this case, the cost of home additions would increase.

Home Addition Cost by Room

The cost of a home addition can vary wildly. One of the biggest factors affecting the cost is the type of addition you build.

Each room requires different features that can affect the costs. For example, a simple mudroom of just drywall and durable flooring is less expensive, on average, than a new kitchen that needs appliances, plumbing, and ventilation.

Here are some average cost ranges by room type:

Room Estimated Cost
Simple bedroom $8,600 to $21,600
Bathroom $6,200 to $90,000
Master suite $25,000 to $100,000
Kitchen $48,000 to $95,000 or more
Living room $17,300 to $43,200
In-law suite $44,000 to $100,000 or more
Sunroom $16,000 to $80,000
Mudroom (50 square feet) $8,000 to $16,000

Adding an In-Law Suite

An in-law suite, which provides a separate living space, is a type of home addition that has been gaining popularity in recent years. It is among the most expensive types of addition, usually costing a minimum of $44,000, but it also adds significant value to your home.


In-law suites that are stand-alone and detached from the primary home generally cost more than attached home additions.

Features such as a small kitchen, living room, and bathroom can make an in-law suite more expensive than a simple bedroom addition. Typically, an in-law suite has its own entrance.

Adding a Sunroom

Sunroom costs can vary widely, from approximately $16,000 to $80,000, depending on the size and materials. Large windows are a common feature of sunrooms, which are generally made from vinyl or aluminum.

Sunrooms, with their versatile uses, can add value to your home, giving an ROI of about 50% to 80%.

Adding a Master Suite

Adding a new master suite can cost between $25,000 and $100,000 (or more). Yet, this is also a valuable addition, with an expected ROI of about 55% nationwide.

Several features can affect the cost of a master suite, with the addition of a bathroom being among the main ones. Also consider the overall square footage, type of closet space (walk-in or reach-in), and whether you will build out on the first floor or build up. Building a vertical addition on the second or third floor is significantly more expensive than building out on ground level.

Adding Another Bathroom

Adding a new bathroom is a popular home addition for homeowners with growing families. Costs can vary widely, ranging from $6,200 to $90,000, with an expected ROI of 50% to 60%.

More affordable bathroom additions have lower-cost features, like simple shower stalls, toilets, sinks, and basic flooring. On the higher end, luxury bathrooms may include high-end features such as a hot tub, double sinks, a walk-in closet, heated floors and towel racks, or a separate room for toilets.

Adding Value to Your Home

A home addition is a great way to upgrade your living space without going through the hassle of buying and selling a house. However, as you can see from the price estimates above, the costs can be significant.

Fortunately, home additions also often add significant value to your property, so you can recoup some of the costs when you resell, and you can build equity.


If you plan to sell your home in the near future, consider the return on your investment when making decisions about which project to complete first.

Frequently Asked Questions (FAQs) 

How much does a 500-square-foot addition cost?

Home additions cost an average of $80 to $200 per square foot. So, you can expect to pay between $40,000 and $100,000 to add a 500-square-foot room to your home. This depends on a lot of factors, such as where you live, how fancy of an addition you want, whether it's a first-floor or second-floor addition, the contractor’s prices, and more.

Is it cheaper to build an addition up or out?

It's significantly cheaper to build out as opposed to building up, which often requires the roof be removed and a staircase installed. You can expect to pay between $80 to $200 per square foot to build out. If you're adding square footage on an upper level, you can expect to pay between $100 to $300 per square foot.

What is the average cost of a home addition?

Expect to pay between $20,900 to $74,000 for a home addition because costs vary widely depending on the type of addition and other factors, such as size, materials, and location.

What home additions add the most value?

Some of the home additions that can provide higher returns on your investment include in-law suites, master bedrooms, and bathrooms. Each of those home addition types has an average return on investment (ROI) of above 50%.

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