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Wall and Ceiling Area Calculator

Convert room dimensions into washable wall and ceiling area, subtract doors and windows as explicit deductions, and convert the area into product.

Inputs

Range: 1–1,000 ft

Inside dimension in feet.

Range: 1–1,000 ft

Inside dimension in feet.

Range: 1–40 ft

Floor to ceiling. A suspended ceiling is measured to the tile line.

Range: 0–100

Enter the measured or label value in the units shown.

Range: 0–200 sq ft

Square feet. A 3 ft by 7 ft door is 21 sq ft; a set of double doors is one 42 sq ft opening or two 21 sq ft ones.

Range: 0–200

Enter the measured or label value in the units shown.

Range: 0–400 sq ft

Square feet. A 3 ft by 5 ft window is 15 sq ft. Measure one and enter it rather than assuming.

Wall washing is often sold without the ceiling. Turn the ceiling off before the product is calculated, not after.

Range: 50–20,000 sq ft per gallon

From the product label or technical data sheet. 1000 sq ft per gallon is typical for a spray, 2000 to 4000 for a mop and scrub.

Range: 1–512

The number after the colon on the product label.

Check the label wording. "1:64 solution" and "1 oz per 64 oz of water" do not mean the same thing.

Range: 0–1,000,000 per gallon

Enter the current purchase price in US dollars for the unit shown.

Result

Ceiling area in scope
600 sq ft
Concentrate needed
0.0146 gal
Chemical cost for this room
$0.26
Gross wall area before deductions
900 sq ft
Doors and windows deducted
102 sq ft
Washable wall area
798 sq ft
Total washable area
1,398 sq ft
Working solution needed
0.93 gal
Reading: what this result means for the job
A full floor of washable surface. Measure one representative office of each type and multiply, because a corridor and a private office of the same floor area do not wash down the same.
Applicability limit
The EPA-registered label governs. Using a registered antimicrobial inconsistently with its labeling is unlawful under 7 U.S.C. 136j(a)(2)(G), and 40 CFR 156.10(i)(2)(ii) requires every label to carry that statement. This tool does arithmetic; it does not approve a dilution, and it does not determine compliance. Wall area is an estimate built on the room dimensions, the wall height and the deductions entered. It does not account for furniture, wall base, radiators, fixed casework or the surface texture, and the wall height is measured to the ceiling tile line, not to the slab above a suspended ceiling. This is a planning figure for the values entered, not a measured result. Coverage rates, product yields and application rates are properties of a specific product, applicator and substrate, and the label or data sheet for the product you are using always takes precedence over the default here.
Check before the job

Working

Gross wall area before deductions
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Doors and windows deducted
—
Washable wall area
—
Ceiling area in scope
—
Total washable area
—
Working solution needed
—
Concentrate needed
—
Chemical cost for this room
—

What to check

  • Measure wall height from the floor to the ceiling tile line, not to the slab above a suspended ceiling.
  • Count every opening, including fire doors and service hatches.
  • Confirm whether the ceiling is in scope: a painted deck and a mineral tile take different products.

Related calculators

Wall and ceiling area is an estimate, and the deductions decide how good it is. Door and window areas are inputs, not site constants, because a 3 ft by 7 ft door and a glazed curtain wall are not the same subtraction. Measure one of each and replace the defaults. The ceiling is a separate switch, because a wall-washing scope that excludes the ceiling should not carry the ceiling in the product figure.