Attic Conversion Cost Calculator

Conversion cost from dormers, insulation, and HVAC.

Attic footprint sq ft

Peak ceiling height (ft)

Dormer type (0-3)

New staircase needed (0/1)

Finish level (0-2)

Floor reinforcement (0/1)

Add bathroom (0/1)

Contingency %

Tab to move between fields

Total conversion cost ($)

$71,040.00

≈ 6 years of state college

Cost per usable sq ft ($)$203.00

Usable sq ft350

Dormer cost ($)$10,000.00

Floor work ($)$5,500.00

Insulation ($)$3,000.00

Staircase ($)$6,000.00

Materials subtotal ($)$42,602.00

Labor cost ($)$19,171.00

Contingency ($)$9,266.00

How to Use This Calculator

Enter your attic's footprint in square feet and the peak ceiling height in feet.
Select the dormer type (none, shed, gable, or hip) -- dormers are the biggest cost driver.
Indicate whether a new staircase is needed and your desired finish level (basic, mid, or high-end).
Toggle optional items like floor reinforcement and bathroom addition, and set your contingency percentage.
Review total cost, cost per usable square foot, and individual line items (dormers, insulation, staircase).

How the result changes with Attic footprint sq ft

Attic footprint sq ft: Total attic floor area (not usable area — that depends on ceiling height).
Peak ceiling height (ft): Height at the tallest point of the roof peak.
Dormer type (0-3): 0 = None, 1 = Single gable dormer, 2 = Two gable dormers, 3 = Full-width shed dormer.
New staircase needed (0/1): 1 = Need to build permanent stairs (pull-down ladder doesn't count), 0 = Stairs exist.
Finish level (0-2): 0 = Basic, 1 = Mid-range, 2 = Upscale (master suite quality).
Floor reinforcement (0/1): 1 = Joists need sistering for floor loads (common), 0 = Floor already rated for occupancy.
Add bathroom (0/1): 1 = Add bathroom (more expensive in attics due to plumbing runs).
Contingency %: Buffer for hidden structural issues (15% recommended for attics).

Total conversion cost ($): All-in cost including labor and contingency.
Cost per usable sq ft ($): Total cost divided by usable square footage (where ceiling > 5ft).
Usable sq ft: Estimated livable area where ceiling height meets code.
Dormer cost ($): Cost of dormers (biggest cost driver for attic conversions).
Floor work ($): Joist reinforcement and subfloor installation.
Insulation ($): Roof and wall insulation (critical for attic comfort).
Staircase ($): Cost of permanent staircase if needed.
Materials subtotal ($): All materials before labor.
Labor cost ($): Estimated labor (40-50% of materials for attic work).
Contingency ($): Buffer for unexpected structural or moisture issues.

Identify Input Parameters
4 parameters
Attic footprint sq ft = 500, Peak ceiling height (ft) = 9, Dormer type (0-3) = 1, New staircase needed (0/1) = 1 = 8 input(s) provided
Calculate Total conversion cost
Total conversion cost = subtotal + contingency
71040 = $71,040
Calculate Cost per usable sq ft
203 = $203
Calculate Usable sq ft
Usable sq ft = atticSF * usableRatio
350 = 350