General Material Calculators

Five everyday estimators on one page: drywall, paint, flooring, stud count and gravel. Adjust waste, product coverage, openings, density, compaction and packaging where relevant. Each shows its formula and assumptions — no signup, nothing blocked.

Drywall sheets

Total area incl. ceiling (ft²)

Sheet size

Waste %

Paint coverage

Paintable area (ft²)

Coats

Coverage (ft²/gal)

Flooring & tile

Room length (ft)

Room width (ft)

Waste %

Tile size

Coverage per box (ft²)

Optional; leave blank for material area only.

Stud count

Wall length (ft)

Wall height (ft)

Spacing (in)

Total opening width (ft)

Optional total width of doors and windows.

Gravel & excavation

Length (ft)

Width (ft)

Depth (in)

Material density

Compaction allowance %

Price per yd³ ($)

Optional.

The formulas

Material	Formula	Typical assumption
Drywall	area × (1+waste) ÷ sheet area	10% waste; 4×8 sheet = 32 ft²
Paint	area × coats ÷ coverage	350 ft²/gal, 2 coats
Flooring	L × W × (1+waste)	10% waste (15% diagonal)
Studs	floor(L×12 ÷ spacing) + 1	16" o.c., plates extra
Gravel	L × W × depth ÷ 27	~2,800 lb/yd³; 10% compaction

Frequently asked questions

How many drywall sheets for a 12×14 room?: Walls ≈ 336 ft² + ceiling 168 ft² ≈ 504 ft² → at 32 ft² per 4×8 sheet with 10% waste, about 18 sheets.
How much gravel for a 12×30 driveway at 4"?: 12 × 30 × ⅓ ft = 120 ft³ ≈ 4.4 yd³, about 4.9 yd³ with compaction allowance — roughly 6.9 tons of crushed stone.
How much paint for a 12×14 room?: ~336 ft² of wall × 2 coats ÷ 350 ft²/gal ≈ 2 gallons.