Basement Finishing Cost Calculator

This free basement finishing cost estimator updates line by line as you enter your size and finish level and add a bathroom or wet bar. Adjusted for your state.

Prices reviewed September 2026
Adjusted for all 50 states
No sign-up to see your number

Step 1 of 4

Your basement

Size, moisture and finish level.

Where is the project?

Labor costs differ a lot by state. This adjusts every line.

Basement area to finish

sq ft

Only count the space you will finish, not mechanical rooms you leave open.

300 sq ft2500 sq ft

Moisture and water

Finish level

Estimated basement cost

$49,700

$33,300 – $66,000

How we calculate your basement finishing cost

We price the project line by line: demolition, cabinetry or fixtures, finishes, labor, permits, and a contingency buffer. Every line has its own low and high unit price, so the range you see comes from real spread in the market, not a flat percentage. Labor is then adjusted by state, and materials move far less by location than labor does.

Unit prices are national benchmark ranges last reviewed September 2026. Treat the result as a planning number for setting a budget and judging contractor bids. It is not a quote. Read our full methodology.

What a basement finishing estimate includes

Framing, insulation, drywall and paint
Flooring, lighting and trim
Bathroom, wet bar and egress windows (optional)
Waterproofing or sump pump (optional)
Permits and a larger contingency buffer

What the basement finishing estimate leaves out

Foundation repairs or structural work
Radon or asbestos remediation
Furniture, appliances and AV equipment
Architect or design fees

Basement finishing cost FAQs

How much does it cost to finish a basement?

Most basements cost roughly $30 to $75 per square foot to finish, so an 800 sq ft basement often lands between $30,000 and $65,000 before a bathroom. Waterproofing, a bathroom and egress windows are the biggest add-ons.

Should I waterproof before finishing?

Yes. If you have any dampness, leaks or a high water table, fix moisture first. Finishing over a wet basement can lead to mold and ruined drywall. Choose "Full waterproofing" or "Needs a sump pump" in the first step to see the cost.

What does a basement bathroom cost?

Usually $8,000 to $25,000. If the basement is below the sewer line you may need a sewage ejector pump, which adds cost.

Do I need egress windows?

If you want a legal bedroom, code requires an egress window or door. Each one typically costs $3,500 to $8,500 installed because the foundation wall must be cut and a window well added.

Does the estimate include permits?

Yes, unless you turn permits off in the last step. Basement finishing almost always needs permits for electrical, plumbing and framing.

Read the basement finishing cost guide