Calculate gross and net vertical wall surface area for one wall, multiple walls, a rectangular room, a measured perimeter, or a known area. Add only the openings you want deducted.
All dimensions are normalized before shared geometry helpers calculate rectangular wall surfaces. Floor and ceiling surfaces are intentionally excluded.
The calculation follows gross area → selected deductions → net area → optional extra allowance. This keeps the measurement useful for many wall-covering projects without estimating a specific material.
gross area = width × height × quantitygross area = 2 × (length + width) × heightgross area = perimeter × heightnet area = gross area − doors − windows − other deductionsplanning area = net area × (1 + extra percentage ÷ 100)A 20 ft × 8 ft wall has 160 ft² of gross wall area.
A 12 ft × 15 ft room with 8 ft walls has a 54 ft perimeter and 432 ft² of gross vertical wall area.
From 432 ft², one 3 × 7 ft door and two 3 × 4 ft windows deduct 45 ft². Net area is 387 ft², and a 10% allowance produces 425.7 ft².
A 5 m × 4 m room with 2.5 m walls has 45 m² gross area. One 1.5 × 1.2 m window leaves 43.2 m² net area.
Small openings are sometimes retained because offcuts or extra material can offset them; this calculator subtracts only rows you add.
For a half wall, enter its actual height. Split irregular walls into rectangles and triangles, then add their areas.
Paint, drywall, insulation, siding, and tile require product-specific coverage and purchase assumptions.
Gross area is the full vertical wall surface before openings. Net area subtracts entered doors, windows, and other excluded areas.
The optional allowance is applied once after deductions. Depending on the project, it may represent cuts, overlap, matching, or contingency rather than waste.
The calculator preserves a square-meter canonical value and displays shared conversions to square feet, square meters, and square yards without hardcoded duplicate factors.
It does not calculate paint, drywall sheets, wallpaper rolls, insulation packages, siding, labor, or code requirements. Follow the related calculator links for those estimates.
Multiply wall width by wall height, then multiply by the number of identical walls.
Multiply 2 × (length + width) by wall height.
Multiply the measured total wall perimeter by wall height.
Only if the intended project benefits from a net area. Small openings are sometimes left in material estimates to offset cuts or extra material.
Subtract entered door, window, and other deduction areas from gross wall area.
No. Wall area measures vertical surfaces; floor area measures horizontal length × width.
Yes. Add wall cards with independent names, dimensions, quantities, and units.
It depends on material, layout, cuts, pattern, and installer guidance. The calculator offers 0%–20% presets and a custom value up to 100%.
No. Use the dedicated Paint or Drywall Calculator for coverage and purchase estimates.