Home Calculators Home Addition Cost Calculator

Home Addition Cost Calculator

Estimate the full cost of your home addition — from foundation to finishes. Get a detailed line-item breakdown by trade, low/mid/high cost ranges, ROI estimates, and permit & financing guidance.

Estimates based on 2024 US national averages — actual costs vary by region, contractor, and specifications

Addition Basics

Define the type, size, and location of your home addition

Addition Type
Size & Dimensions
Addition footprint: 320 sq ft Interior wall perimeter: 72 lin ft
Location & Region

Structural & Foundation

Foundation type and structural framing choices

Rooms & Interior Features

Check all features included in your addition

Bathrooms
Kitchen & Wet Areas
Windows & Doors
Included Features (check all that apply)

Mechanical, Electrical & Plumbing

MEP systems scope for your addition

Interior Finishes

Floor, wall, and trim finish selections

Permits, Design & Professional Fees

Soft costs that are often forgotten in budgets

Estimated Total Cost
mid-range estimate
Cost Range
Low
Mid
High
Cost Per Sq Ft (mid)
per square foot

Project Summary

Addition Size
Addition Type
Quality Level
Region Multiplier
Est. Timeline
ROI Estimate

Cost by Category (mid)

Where Your Budget Goes

Structural
—%

2024 National Cost Benchmarks

Room Addition (avg)$80–200/sqft
Bathroom Add$20k–75k
Master Suite$100k–250k+
Second Story$150–300/sqft
Sunroom$30k–80k
ADU / In-Law Suite$60k–200k
Garage Addition$25k–50k