Skip to content
Need a Renovation Cost Estimate?

How Much Does It Cost to Build a Duplex?

$150 - $300
cost to build a duplex (SF)
$400,000 - $1,500,000
average total cost to build a duplex
Get your renovation costs using Renotag's renovation cost calculator:

Key Takeaways

Key PointDetails
Cost Per Square Foot$150 – $300
Total Average Cost$300,000 – $600,000
National Average Cost$400,000
Minimum Cost$100,000
Maximum Cost$1,500,000

Building a duplex can provide a great investment opportunity and additional living space. Understanding the costs involved and the different options available can help you plan your duplex construction project effectively.

Average Cost to Build a Duplex

The cost to build a duplex varies based on the size and type of duplex. Below is a breakdown of average costs:

Average Cost to Build a Duplex

National Average Cost$400,000
Minimum Cost$100,000
Maximum Cost$1,500,000
Average Cost Range$300,000 – $600,000

Cost to Build a Duplex by Size

The size of the duplex significantly affects the overall cost.

Total Square FootageAverage Total Cost*
1,000$150,000 – $280,000
2,000$300,000 – $560,000
3,000$450,000 – $840,000
4,000$600,000 – $1,120,000
5,000$750,000 – $1,400,000

Cost to Build a Duplex by Type

Different types of duplexes come with varying costs, depending on their design and construction.

TypeAverage Cost Per Square Foot*
Unit-over-unit$150 – $190
Side-by-side$160 – $280

Unit-over-Unit Duplex

A unit-over-unit duplex has one unit on top of the other, typically providing a more compact footprint.

Side-by-Side Duplex

A side-by-side duplex has two units next to each other, offering more privacy and potentially more square footage per unit.

Duplex Building Cost Factors

Several factors influence the overall cost of building a duplex, including materials, labor, and additional features.

FactorAverage Cost Per Square Foot
Foundation$5.00 – $33.00
Framing$11.00 – $30.00
Drywall$1.50 – $3.50
Flooring$4.00 – $15.00
Plumbing$4.00 – $5.00
Interior Trim$4.00 – $10.00
Siding$4.00 – $13.00
Roof$3.00 – $6.00
Insulation$1.00 – $4.50
Electrical Wiring$4.00 – $9.00
HVAC System$3.00 – $6.00
Interior Painting$1.00 – $3.00
Countertops$50.00 – $150.00
Driveway$3.00 – $12.00
Garage$35.00 – $60.00
Doors$225 – $1,900 each
Windows$450 – $1,500 each
Light Fixtures$70 – $300 each
Toilets$350 – $800 each
Sinks$330 – $1,300 each
Cabinets$150 – $500 per linear foot
Appliances$2,500 – $6,800 per kitchen

Labor Cost to Build a Duplex

Labor costs vary based on the complexity of the project and the region.

Converting a Single-Family Home into a Duplex

Converting a single-family home into a duplex can be a cost-effective way to add living space and increase property value. This process typically involves adding walls, separate entrances, and additional kitchens and bathrooms.

Duplex Building FAQs

Is Building a Duplex Worth It?

Yes, building a duplex can be a worthwhile investment. It provides rental income potential, increases property value, and can offer flexible living arrangements for extended families or tenants.

How Long Does It Take to Build a Duplex?

Building a duplex typically takes 6 to 12 months, depending on the complexity of the design, the size of the project, and the availability of materials and labor.

Is It Cheaper to Buy or Build a Duplex?

Building a duplex can be more cost-effective in the long run, as it allows for customization and potentially lower maintenance costs. However, buying an existing duplex can provide immediate rental income and may be less expensive upfront.

How Big of a Down Payment Do You Need to Build a Duplex?

The down payment required to build a duplex varies based on the loan type and lender requirements. Typically, you may need 20% to 25% of the total construction cost as a down payment.

Getting Estimates from Duplex Construction Companies

When seeking estimates for your duplex construction, consider the following tips:

  1. Get Multiple Quotes: Compare prices and services from different contractors.
  2. Check References: Look for reviews and testimonials from previous clients.
  3. Verify Credentials: Ensure the contractor is licensed, insured, and experienced in duplex construction.
  4. Ask About Customization: See if they offer custom solutions to meet your specific needs.

Questions to Ask Duplex Builders

  • How long have you been in business?
  • Can you provide references from similar projects?
  • What services are included in your standard package?
  • Do you offer any specialized duplex designs?
  • What are your rates for additional services?
  • How do you handle unexpected issues or additional requests?

Cost to Build a Duplex Summary

Building a duplex can provide a great investment opportunity and additional living space. By understanding the costs, benefits, and available options, you can make an informed decision that meets your needs and budget.

For more information on duplex construction and to explore other cost-related guides, visit our detailed articles on home improvement cost and multi-family home construction cost.

Relevant Internal Links

Renotag's renovation cost calculator being used by a person to price their home renovation costs.
social proofs renotag
5K+ homeowners trust Renotag

Your renovation cost is waiting

The world's first renovation cost calculator.

Table of Contents

Calculate your reno price

Add your project details, choose your finishes, and get a price for your project – no contractor needed until construction time.