How Much Does Converting a Duplex to a Single-Family Home Cost in 2025?

This article was updated using automation technology and thoroughly reviewed for accuracy by HomeAdvisor Editor Ryan Noonan.

The average cost of converting a duplex to a single-family home runs between $50,000 and $135,000, depending on labor rates, project scope, and finish level. The work can include anything from removing a second kitchen to rerouting plumbing and electrical lines. Knowing these cost drivers early helps you build a realistic budget and keep the project on track.

Simple cosmetic conversions—think removing an extra kitchen and taking down a few non-load-bearing walls—can cost as little as $20,000. A full gut job that strips the home to the studs and rebuilds every room can push the total to $200,000 or higher.

Cost Factors for Converting a Duplex to a Single-Family Home 

How much you’ll spend on duplex conversion depends on a variety of factors. Here’s a closer look at how your costs break down.

Scope

Project scope is the biggest driver: a quick kitchen removal and a few wall changes cost far less than a full gut renovation. Some homeowners use a duplex conversion as an opportunity for a bigger remodeling project, while others simply want to join to spaces as-is with minimal renovation work.

Demolition

Budget $2 to $7 per square foot to tear out interior walls, haul away debris, and cover equipment costs. Depending on the scope of your duplex conversion, you may have only a minor interior demolition job to do, while more robust remodels can involve a much more complex demolition project.

Adding Walls

Installing new drywall runs $1 to $3 per square foot. Depending on the size of your home and your project scope, you may have only a few walls to reconstruct, while full remodeling projects will have significant drywall and wall framing needs. 

Permits

Permitting is a critical part of converting a duplex to a single-family home. You’ll need building permits as well as electrical, plumbing, and possibly zoning permits. Permit costs vary widely by location, from $150 to $7,000 for a project of this size. Inspections are also required at several stages to ensure code compliance. Failing to secure proper permits can result in fines or costly rework.

Heating and Air

Expect to pay $3,800 to $7,500 for a new HVAC system. You’ll also spend $10 to $20 per square foot for any ductwork changes that come from merging two separate systems into one. 

Finishes

Finishing touches average $10 to $60 per square foot, depending on the task and the quality of materials you choose. Plan for these finishing costs in your budget:

• Flooring

• Paint

• Cabinets

• Fixtures

• Trim 

Materials

Your choice of materials—standard drywall or plaster, builder-grade or premium fixtures—can move the needle on your budget.

Labor Costs

Specialized pros for plumbing, electrical, and structural work add to the price tag, and coordinating multiple trades can become a project in itself. Here are some of the main pros you’ll need to hire to tackle your duplex conversion project.

Construction Manager 

Set aside 10% to 20% of your total budget for a construction manager or general contractor. On a $50,000 project, that’s $5,000 to $10,000 for professional oversight, quality assurance, and coordinating the other laborers on your project.

Architect 

Plan to bring in an architect early to map out the new floor plan. Architect fees run $100 to $250 per hour, or roughly $7,000 to $20,000+ for a standard duplex conversion. Any major structural or layout changes will need stamped drawings to pass local code reviews.

Electrical

Licensed electricians charge $50 to $150 per hour. You’ll need to hire an electrician for tasks like consolidating two service panels into one, rewiring, and installing a new panel.

Plumbing

Plumbers cost $45 to $200 per hour. Merging two plumbing systems can be as simple as tying sewer lines together, but relocating fixtures will drive costs higher.

Does a Duplex Conversion Increase Home Value?

A conversion pencils out when the expected value boost outweighs your renovation spend. Average duplex conversion projects see a 50% to 75% ROI, so stack your estimated budget against recent sales of comparable single-family homes in your neighborhood. If the math shows a healthy gap, the project likely makes sense. Always factor in local market trends and resale demand before you commit.

Ways to Save on Duplex Conversion Costs

Consider these cost-saving strategies to make your duplex conversion more budget-friendly:

• Obtain at least three detailed quotes from local general contractors to ensure competitive pricing.

• Stick with builder’s grade or mid-range finishes instead of choosing luxury materials.

• Keep your floor plan simple rather than opting for highly customized layouts and designs.

• Handle simpler finishing tasks, like painting, yourself to reduce labor costs.

DIY Duplex Conversion vs. Hiring a Building Pro

Handy homeowners may be tempted to tackle a duplex conversion on their own, but leave complex jobs—like rewiring or re-plumbing—to licensed pros. Even smaller tasks call for solid project management skills. A seasoned general contractor keeps the work on schedule, up to code, and on budget.

How HomeAdvisor Gets Its Cost Data

No place is more important than your home, which is why HomeAdvisor connects homeowners with local pros to transform their houses into homes they love. To help homeowners prepare for their next project, HomeAdvisor provides readers with accurate cost data and follows strict editorial guidelines. After a project is complete, we survey real customers about the costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.