Quick Answer: An attic conversion costs $20,000–$80,000 depending on scope and size. A basic 400 sq ft conversion runs about $20,000–$30,000. Materials cost $20–$70/sq ft depending on scope. Labor runs $12–$25/sq ft using carpenter rates of $21.77–$31.75/hr nationally. Fixed costs add $3,900–$12,800 for staircase, structural work, electrical, HVAC, permits, and insulation. A 20% contractor markup applies to the total. Enter your ZIP for location-specific pricing.
Calculate how much an attic conversion costs. Select your conversion scope, enter the usable square footage and ZIP code for a location-specific estimate with a full cost breakdown.
Attic Conversion Cost by Scope
Installed cost per square foot including materials, labor, and fixed costs for a typical 400 sq ft attic:
| Scope | Material $/Sq Ft | Fixed Costs | Total (400 Sq Ft) |
|---|---|---|---|
| Basic | $20/sq ft | $3,900 | $20,000–$28,000 |
| Standard | $40/sq ft | $8,600 | $38,000–$52,000 |
| Premium | $70/sq ft | $12,800 | $60,000–$80,000+ |
How Attic Conversion Cost Is Calculated
- Materials: Square footage × material rate per sq ft ($20–$70 depending on scope). Basic covers drywall, flooring, and trim. Standard adds upgraded flooring, lighting, and better insulation. Premium includes hardwood, custom built-ins, and bathroom fixtures.
- Labor: Square footage × hours per sq ft (0.30–0.75) × hourly rate × 1.5 burden. Premium scopes need more labor hours due to custom work, dormers, and bathroom plumbing.
- Fixed costs: Staircase ($2,000–$4,000), structural reinforcement ($0–$2,500), electrical ($500–$1,500), HVAC extension ($1,000–$3,000), permits ($400–$800), and insulation upgrades ($0–$1,000).
- Contractor markup: 20% for general contractor overhead, profit, and project management.
What Each Scope Includes
- Basic: Insulation between rafters, drywall on walls and ceiling, laminate or vinyl plank flooring, basic staircase, and minimal electrical (lighting and outlets). No structural changes, HVAC, or plumbing. Best for a simple bonus room or home office.
- Standard: Everything in basic plus structural reinforcement of floor joists, dedicated HVAC zone, upgraded electrical panel, code-compliant egress windows, better insulation (spray foam), and mid-grade finishes. Suitable for a bedroom or family room.
- Premium: Full build-out with dormer additions for added headroom, hardwood flooring, full bathroom with plumbing, custom staircase, premium insulation, recessed lighting, and high-end trim. Creates a true master suite or self-contained living space.
Fixed Cost Breakdown by Scope
| Item | Basic | Standard | Premium |
|---|---|---|---|
| Staircase | $2,000 | $3,000 | $4,000 |
| Structural | $0 | $1,500 | $2,500 |
| Electrical | $500 | $1,000 | $1,500 |
| HVAC | $1,000 | $2,000 | $3,000 |
| Permits | $400 | $600 | $800 |
| Insulation | $0 | $500 | $1,000 |
| Total Fixed | $3,900 | $8,600 | $12,800 |
Formula Summary
Attic Conversion Cost Formula: Total installed cost includes materials (per sq ft), burdened labor, and fixed costs for staircase, structural, electrical, HVAC, permits, and insulation, multiplied by contractor markup.
Total = (A × M + A × H × R × 1.5 + F) × 1.20
where A = square footage, M = material cost/sq ft, H = labor hours/sq ft, R = hourly trade rate, 1.5 = labor burden, F = fixed costs, 1.20 = markup.
| Scope | Material $/sq ft | Labor hr/sq ft | Fixed Costs |
|---|---|---|---|
| Basic | $20 | 0.30 | $3,900 |
| Standard | $40 | 0.50 | $8,600 |
| Premium | $70 | 0.75 | $12,800 |
Constants: Labor burden 1.5×. Contractor markup 20%. Fixed costs include staircase, structural reinforcement, electrical, HVAC, permits, and insulation upgrades. Trade: carpenters (SOC 47-2031), national mean $27.30/hr. Rates from BLS OEWS May 2024, 393 metros.
Carpenters Hourly Rates by Metro (BLS OEWS May 2024)
| Metro | 25th %ile | Mean | 75th %ile |
|---|---|---|---|
| New York | $27.07 | $37.32 | $46.01 |
| Los Angeles | $26.91 | $36.97 | $47.02 |
| Chicago | $24.11 | $38.11 | $51.92 |
| Dallas | $20.33 | $24.01 | $26.76 |
| Houston | $22.32 | $24.93 | $28.40 |
| Washington | $23.86 | $30.71 | $34.34 |
| Philadelphia | $24.09 | $32.62 | $36.99 |
| Miami | $20.50 | $24.57 | $27.85 |
| Atlanta | $22.03 | $24.84 | $28.25 |
| Phoenix | $22.72 | $28.74 | $34.55 |
Related Calculators
- Insulation Calculator — calculate insulation batts or rolls for your attic
- Drywall Calculator — estimate drywall sheets for walls and ceiling
- Hardwood Floor Cost Calculator — price hardwood flooring for the finished attic
- Home Addition Cost Calculator — compare attic conversion vs. building an addition
Estimates are for planning purposes only. Consult a qualified contractor for critical projects. Actual material requirements may vary based on site conditions, waste, and installation methods.
Pricing last verified: February 2026. Material prices vary by region, season, and supplier. Prices shown are national averages for planning purposes.