Home Addition Cost Calculator

Estimate costs for adding square footage to your home — room additions, second stories, bump-outs, and sunrooms.

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About This Calculator

This calculator provides cost estimates based on national averages and typical pricing for 2026. Actual costs vary by location, contractor, material availability, and project complexity. Always get 3+ quotes from licensed contractors.

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Frequently Asked Questions

How accurate is this estimate?
This calculator uses national average costs and provides a ballpark estimate within 15-25% accuracy. Your actual costs depend on local labor rates, material prices, project complexity, and contractor availability. Always get professional quotes for your specific project.
Should I hire a contractor or DIY?
It depends on the project scope and your skill level. Cosmetic work (painting, minor repairs) is great for DIY. Structural, electrical, plumbing, and roofing work should be done by licensed professionals for safety and code compliance. Permits are usually required for major work.
Do I need permits?
Most significant home renovations require building permits. Structural changes, electrical work, plumbing modifications, and additions almost always need permits. Cosmetic changes (paint, flooring, fixtures) usually don't. Check with your local building department.