Home Addition Cost
Calculator
Estimate your home expansion budget instantly. Select addition type, square footage, and finish level for a detailed cost breakdown.
How It Works
Get your home addition estimate in three simple steps.
Pick Your Addition
Choose from bedroom, bathroom, kitchen, sunroom, garage, or second-story additions.
Set Size & Finish
Adjust square footage, choose your finish level, and select a foundation type.
See Your Estimate
Instantly get low, mid, and high estimates with a full cost breakdown by category.
Cost by Addition Type (2026)
Typical cost-per-square-foot ranges for the most common home addition types at mid-range finish level.
| Addition Type | Low ($/sqft) | High ($/sqft) |
|---|---|---|
| Bedroom | $150 | $250 |
| Bathroom | $200 | $350 |
| Kitchen | $250 | $400 |
| Sunroom | $120 | $200 |
| Garage | $80 | $150 |
| Second Story | $200 | $350 |
These ranges reflect mid-range finish levels. Budget finishes reduce costs by ~20%; luxury finishes may increase them by 70% or more.
2026 Home Addition Cost Guide
Planning a home addition is one of the most significant investments you can make in your property. In 2026, costs have stabilized somewhat after the post-pandemic volatility, but labor shortages continue to keep prices firm in many markets. A well-planned addition not only gives you the extra space you need but can also significantly increase your home's resale value.
Breakdown by Addition Type
Bedrooms & Suites: Adding a ground-floor primary suite is one of the most popular projects for aging-in-place. Expect to pay $150–$250 per square foot. The cost increases if you need to tie into existing plumbing for an en-suite bathroom.
Kitchen Expansions: Kitchens are the most expensive rooms to build because they require extensive plumbing, electrical work, heavy appliances, and cabinetry. Costs can easily exceed $300 per square foot for high-end finishes.
Sunrooms: A three-season room is a cost-effective way to add square footage ($120–$180/sqft), but if you want a four-season room with full HVAC integration and insulation, the cost approaches that of a standard room addition.
Garages: Attached garages are generally cheaper to build per square foot ($80–$150) because they often don't require the same level of insulation, flooring, or drywall finishing as living spaces.
Hidden Costs to Watch For
- Site Preparation: Excavation, tree removal, and grading can add $1,500–$5,000 before pouring a drop of concrete.
- Permits & Architectural Fees: Don't forget to budget 10–15% of your total project cost for plans, engineering stamps, and city permits.
- Utility Upgrades: Adding a new room might require upgrading your electrical panel to 200 amps or installing a larger HVAC system.
Factors That Affect Cost
Several variables influence the final price of a home addition beyond square footage and room type. Understanding these helps you set realistic expectations.
Finish Level
Budget materials (laminate, builder-grade) cost far less than luxury selections (quartz, custom cabinetry).
Foundation Type
Slab is most affordable. Crawl spaces add ~$8,000; full basements can add $20,000+.
Location & Labor
High-cost areas (SF, NYC) can be 50–100% higher than national averages.
Permits & Fees
Most municipalities require building permits — typically $500–$2,000 base plus per-sqft charges.
Project Complexity
Moving load-bearing walls, rerouting plumbing, or matching historical architecture adds premium costs.
Seasonal Timing
Off-season construction (late fall/winter) can sometimes yield lower contractor bids.
Frequently Asked Questions
Common questions about home addition costs answered.
Planning a countertop upgrade?
Use our Countertop Square Footage Calculator to measure accurately before ordering materials.