How Much Does It Cost to Finish an Attic in 2025?

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

Finishing your attic is one of the quickest ways to gain extra square footage and increase your home’s value. Most homeowners spend between $7,500 and $35,000—or $30 to $60 per square foot—with a national average of $20,000. Your total costs depend primarily on the size of your attic, the materials you choose, and local labor rates. Plan your budget upfront and rely on a qualified remodeling professional to ensure the project is safe and compliant with local codes.

Attic Finishing Cost Factors

The total cost to finish your attic depends on various factors, including square footage, labor, and permits. Here is a breakdown of the cost factors that will determine your final costs.

Size

Size is the most significant factor in determining price. At $30 to $60 per square foot, converting a standard attic runs $4,000 to $16,000. If you’re aiming for a fully equipped living space with built-ins, high-end finishes, and plumbing, costs can climb to $200 per square foot.

Materials

Expect materials and labor to cost between $30 and $60 per square foot. Upgrading to custom trims, premium flooring, or built-ins can increase the total closer to $200 per square foot.

Labor

Plan on the cost of a general contractor to consume roughly 10% to 20% of the budget, but that increases if your project requires plumbing, electrical upgrades, or structural fixes.

Permits

Set aside $100 to $1,500—or more in some cities—for the cost of building permits. You’ll almost always need them for electrical, ventilation, plumbing, or structural changes.

Cost to Finish an Attic by Task

Your attic’s current condition and your end goal dictate which of these line items you’ll need. Below are the most common costs associated with each task.

Subflooring

Expect to pay between $3 and $10 per square foot for the cost to install a subfloor. You’ll need one anytime joists are exposed, and adding insulation beneath it boosts energy efficiency and mutes noise.

Electrical

Budget $750 to $3,200 for an electrician to run wiring, add outlets, or install light fixtures. 

Drywall

Drywalling costs an average of $2,100 and is installed after wiring, insulation, and ventilation are in place.

Insulation

Attic insulation costs $2,500. Blown-in insulation is most cost-effective in partially finished spaces. Structural insulated panels are pricier but more durable and energy-efficient.

Windows

Dormer additions cost between $8,000 and $30,000 each.

Floor Joists

Repairing or replacing floor joists averages $6,000. Joists must support 30 pounds per square foot of live load, plus the weight of finishes and furnishings.

Plumbing

Plumbing costs range from $1,000 to $10,000, depending on the rough-in status, line distance, and number of fixtures.

HVAC

If you plan to extend your HVAC system into the attic, budget $1 to $3 per square foot for the cost of new ductwork, $2,500 for attic insulation fees, and $3,000 for the price of a new mini-split system.

Does a Finished Attic Increase Home Value?

Finishing an attic can significantly increase your home’s value, especially when it adds usable square footage, like an extra bedroom, office, or flex space. Buyers are drawn to finished attics that feel like a natural extension of the home, complete with proper insulation, adequate lighting, and convenient access. While the return on investment varies, converting an attic is often more cost-effective than building an addition. It can offer a substantial resale boost if done to code and with permits.

DIY Attic Finishing vs. Hiring a Pro

You could reduce labor costs by 40% if you tackle finishes like painting or flooring yourself, but leave code-driven electrical or plumbing work to licensed professionals. Hire a home remodeling professional near you to ensure that critical safety and compliance elements are addressed. 

Contact a local remodeling professional to ensure your attic finishing project is handled safely and correctly.

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.