Finishing or converting an attic costs a national average of $20,000 per Angi’s 2026 data, with most projects landing between $7,500 and $35,000.1 Thumbtack’s users pay $9,579 on average. Prices below are national figures* for 2026.
*National figures, not local quotes; Angi and Thumbtack label their data 2026 (Thumbtack updated July 10, 2026), and HomeGuide’s page was updated February 11, 2026. Your price depends on the space you are creating, structural work needed, and finish level.
$20,000
average (Angi)
$7,500 – $35,000
typical range (Angi)
$9,579
average (Thumbtack)
$50 – $150
per sq ft (HomeGuide)
What sources say
| Source | Figure | Scope |
|---|---|---|
| Angi | $20,000 average; $7,500 – $35,000 typical | Professional attic finishing, all conversion types (2026 data) |
| Thumbtack | $9,579 average; $4,224 – $23,012 range | Attic remodel projects on its platform (2026) |
| HomeGuide | $15,000 – $75,000 total; $50 – $150 per sq ft | Full finish including labor and materials (updated February 2026) |
The averages sit far apart — $9,579 versus $20,000 — and the sources do not establish how much of the gap reflects project mix versus pricing. Thumbtack’s figures span small jobs (its low end is $1,263), while Angi’s center on complete finishing projects.1,3
Cost per square foot
| Source | Per-square-foot range |
|---|---|
| Angi | $30 – $60 (basic finish; up to $200 for a full living area) |
| HomeGuide | $50 – $150 (total, labor and materials) |
The two per-square-foot ranges disagree; Angi’s covers standard finishing tasks while HomeGuide’s is an all-in total, and neither fully explains the gap.1,2
Cost by conversion type (Angi, 2026)
| Conversion type | Average cost |
|---|---|
| Storage space | $4,800 – $22,000 |
| Above-garage bonus room | $4,600 – $24,000 |
| Bedroom | $9,000 – $65,000 |
| Office | $10,000 – $40,000 |
| Bathroom | $9,800 – $56,000 |
| Primary bedroom suite | $27,000 – $80,000 |
| Loft conversion | $10,000 – $75,000 |
| Dormer addition | $8,000 – $30,000 |
HomeGuide’s room-purpose figures run in the same direction: storage $5,000 to $20,000, bedroom/office/bonus room $20,000 to $45,000, bathroom $20,000 to $60,000, and a primary suite $50,000 to $100,000+.2
Professional and structural costs
| Professional / task | Cost (source) |
|---|---|
| General contractor | 10% – 20% of project (both Angi and HomeGuide); $300 – $500 per day (Angi) or $50 – $150 per hour (HomeGuide) |
| Structural engineer | $100 – $220 per hour (HomeGuide); about $100 per hour (Thumbtack) |
| Electrician | $750 – $3,200 (Angi) |
| New staircase (if required) | up to $10,000 (Thumbtack) |
Thumbtack notes floor joists must support 30 pounds per square foot for a finished space and that your local building inspector has the final say, so check code requirements before starting.3
Does a conversion pay off?
According to National Association of Realtors figures cited by Thumbtack, converting attic space into a bedroom with a small bath carries a national median cost of $65,000 and retains 61 percent of its value at resale.3
Related guides
Second Story Addition Cost (2026 Guide)
Attic Insulation Cost
Basement Finishing Cost
Attic Ladder Installation Cost
All cost guides
Sources
1. Angi — How Much Does It Cost to Finish an Attic? (2026 Data)
2. HomeGuide — Cost to Finish an Attic (2026)
3. Thumbtack — Attic Remodeling Cost (2026)