Flooring & Walls Calculators
Interior projects live or die by the cut list. Estimate flooring boxes room by room, tile with pattern waste, drywall sheets together with the mud, tape and screws that go with them, and the gallons of paint and primer to finish the walls.
- Flooring CalculatorCalculate vinyl plank (LVP) or laminate flooring for multiple rooms and stairs. Get square footage with waste, number of boxes and stair nose pieces.Open calculator
- Tile CalculatorHow many tiles do you need? Calculate tiles and boxes for floors, shower walls and backsplashes with grout joints, pattern waste, grout and thin-set.Open calculator
- Drywall CalculatorHow many sheets of drywall do you need? Calculate 4×8, 4×10 or 4×12 sheets for walls and ceiling, plus joint compound, tape and screws.Open calculator
- Paint CalculatorHow much paint do you need? Get gallons and quarts for a room's walls minus doors and windows, plus the ceiling and primer, for one, two or three coats.Open calculator
Measure once, add waste once
Interior estimates go wrong in two ways: measuring the wrong surface and stacking waste factors. Measure floors wall to wall at the baseboard and split odd shapes into rectangles. Then add one waste allowance that matches the layout — about 10% for straight plank or tile, 15–20% for diagonal or herringbone patterns, and 10–15% for drywall.
Order of work
Hang and finish drywall before installing flooring, and tile wet areas before running plank floors up to them. The drywall calculator includes joint compound, tape and screws; the tile calculator includes grout and thin-set; and the flooring calculator handles multiple rooms and stairs.
Buy from one lot
Tile and plank flooring vary slightly between production runs. Buy everything from the same lot number and keep a spare box for future repairs.
A worked example: one 12 × 14 ft room
The floor is 12 × 14 = 168 sq ft. With a 10% allowance that becomes 184.8 sq ft, so with flooring sold in 20 sq ft cartons you need 10 cartons (9.24 rounded up). For drywall in the same room with 8 ft walls, the walls are (12 + 14) × 2 × 8 = 416 sq ft and the ceiling another 168, for 584 sq ft. Deduct one 3 × 7 ft door (21 sq ft) to get 563 sq ft; add 10% and divide by 32 sq ft per 4 × 8 sheet, and you need 20 sheets.
Choosing a waste allowance
- Plank flooring: one hardwood maker suggests about 5% for straight installs in simple rooms and 10–15% for diagonal layouts; character grades and rooms with many corners need more.
- Tile: our tile calculator uses 10% for a straight grid, 12% for offset, 15% for diagonal and 20% for herringbone.
- Drywall: 10% covers typical cut-offs; larger sheets mean fewer seams but more waste in small rooms.
Setting materials add up
Tile and drywall need more than the panels or tiles themselves. Thin-set coverage depends on trowel size — one major brand lists about 90–100 sq ft per 50 lb bag with a ¼ × ¼ in square notch but only about 42–47 sq ft with a ½ × ½ in notch for large tiles. For drywall, a major gypsum maker lists roughly 370 ft of paper tape per 1,000 sq ft of board. The calculators include these so the whole shopping list comes out in one pass, and each lists its sources.
Paint: the last step on the walls
Once the drywall is finished, paint is estimated from the same wall area: perimeter × height, minus doors and windows. Interior latex typically lists 350–400 sq ft per gallon per coat on a smooth, sealed wall, and two coats is the norm over new drywall or a color change. In the 12 × 14 ft room above, the walls less one door and two windows are 365 sq ft, so two coats is about 2.1 gallons. New drywall also needs primer, or a self-priming paint applied as two coats. The paint calculator works out gallons and quarts for the walls, ceiling and primer.
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