Room Addition Cost Calculator
Estimate the cost of adding a room to your home based on square footage, finish level, and your location.
Last updated: March 25, 2026
Room Addition Cost Calculator
Estimate the cost of adding a room to your home based on square footage, finish level, and your location.
Estimated Total
$57,000
Itemized Breakdown
This calculator provides estimates based on national averages adjusted for your region. Actual costs may vary significantly based on specific project conditions, contractor availability, material prices, and local market factors. Always get at least 3 quotes from licensed, insured contractors before starting your project.
Want the full picture?
Read our complete Room Addition cost guide with material comparisons, contractor tips, savings strategies, and regional pricing data.
Quick Cost Reference
Cost by Tier
Basic 200 sq ft room addition with standard materials, vinyl siding to match, builder-grade windows, basic electrical and HVAC extension
300 sq ft addition with mid-grade finishes, fiber cement siding, energy-efficient windows, dedicated HVAC zone, recessed lighting
400 sq ft addition with premium finishes, custom millwork, high-end windows, radiant floor heating, full architectural design, custom built-ins