Home Mold Remediation Cost Calculator Per Square Foot

Measure the moldy area first, not the size of the room. Add a foot or two around the visible growth, because crews cut beyond what you can see.

1. Enter the affected area in square feet. The worked example uses 100 sq ft.
2. Choose the severity. Low is surface mold at $10 per sq ft, medium is mold that has reached the material at $15 per sq ft, and high is heavy or structural mold at $25 per sq ft.
3. Check the cost per square foot. Changing the severity sets this rate, and you can still edit it if a contractor quoted you a different rate.
4. Enter the inspection and testing fee. The default is $300, which sits inside the usual $250 to $700 range for a clearance test.
5. Enter any containment or repair allowance, or leave it at $0 if your quote already covers it.
6. Press Calculate, or press Enter. The total cost appears first and large, with the remediation cost, the effective cost per square foot and the low to high range below.

Professional mold remediation is usually priced per square foot of affected area, and the most quoted planning range is $10 to $25 per square foot. HomeAdvisor reports that range, and this calculator uses it for the low to high range and for the three severity rates.

Remediation cost = affected area x cost per square foot. Total cost = remediation cost + inspection and testing fee + containment or repair allowance. Effective cost per square foot = total cost / affected area. The low end of the range uses $10 per sq ft in place of your rate, and the high end uses $25.

Low severity uses $10 per sq ft, medium uses $15, and high uses $25. The rate stays editable, so you can type in a quoted rate instead. The range never changes with the rate you type, because it is always built from $10 and $25. If moldy drywall has to come out, our drywall calculator works out how many sheets the rebuild needs.

A homeowner finds mold on 100 sq ft of basement wall after a slow leak is fixed. The severity is medium, the inspection and testing fee is $300, and there is no extra allowance.

1. Severity sets the rate. Medium mold uses $15 per sq ft.
2. Remediation cost: 100 sq ft x $15 = $1,500.
3. Total cost: $1,500 + $300 testing fee + $0 allowance = $1,800.
4. Effective cost per square foot: $1,800 / 100 sq ft = $18.
5. Low end of the range: 100 x $10 + $300 = $1,300. High end: 100 x $25 + $300 = $2,800.

As a second check, take 40 sq ft at a quoted rate of $20 per sq ft, with a $300 testing fee and a $200 allowance. The remediation cost is $800, the total is $1,300, the effective cost is $32.50 per sq ft, and the range is $900 to $1,500.

The affected area moves the total in a straight line. At the medium rate of $15 per sq ft, 50 sq ft costs $750 for remediation, 100 sq ft costs $1,500, and 200 sq ft costs $3,000, before any fees. That is why measuring carefully matters.

Severity moves the rate more than anything else. The same 100 sq ft costs $1,000 at the low rate of $10, $1,500 at the medium rate of $15, and $2,500 at the high rate of $25. Severe jobs need more containment, more removal, and more drying time, which is what the higher rate pays for.

Where the mold is matters too. Bathrooms usually run $500 to $1,000, basements $500 to $3,000, attics $1,000 to $4,000, and HVAC systems $3,000 to $10,000. A typical residential job lands around $1,200 to $3,750, while a whole house job can reach $10,000 to $30,000. Our bathroom remodel cost calculator and our kitchen remodel cost calculator help you price the rebuild once the wall is open, since remediation alone does not put the room back together.

The U.S. Environmental Protection Agency draws the line at about 10 square feet, which is roughly a 3 ft by 3 ft patch. Below that size you can usually clean the mold yourself, provided you fix the water problem first and wear an N95 respirator, gloves, and eye protection. Above that size, bring in a contractor experienced in mold cleanup.

The EPA splits larger jobs into two more bands. Areas from 10 to 100 sq ft need limited containment, and areas over 100 sq ft need full containment with sealed barriers and negative air pressure. That is why a 100 sq ft job sits at the top of the middle band in the worked example.

Fix the moisture source before any cleanup starts, or the mold comes back and you pay twice. A leaking pipe, a roof leak, or a faulty water heater can all feed the same patch. Our water heater replacement cost calculator prices a new unit if a leaking heater is the cause. Dead mold can still cause allergic reactions, so killing it is not enough. It has to be removed, which is why wet drywall and insulation come out instead of being sprayed.

Get at least three written quotes and compare them on the same scope, not just the bottom line. Each quote should list the square feet to be removed, the containment setup, HEPA cleaning and drying, the clearance test, and whether rebuilding is included. A quote that only sprays a chemical over wet drywall is not remediation.

Ask who does the clearance test, and get the result in writing before the wall is closed. An independent tester, not the remediation company, avoids a conflict of interest. Also check your insurance before you file a claim. Most policies pay only when the mold follows a sudden covered water loss, and many cap mold at $5,000 or $10,000, so a $1,800 job may cost less out of pocket than the claim is worth.

Finally, confirm the moisture fix is in the plan and priced by the right trade. Remediation gets the mold out, and a plumber, roofer, or builder fixes the leak and rebuilds the wall.