Free calculators for paint, concrete, flooring, gravel, and fencing projects. Get accurate material estimates and cost breakdowns before you buy.
Calculate gallons of paint needed for any room based on dimensions, number of coats, and doors/windows.
Calculate cubic yards and number of bags needed for slabs, footings, and columns. Includes waste factor.
Calculate tons and cubic yards of gravel, sand, topsoil, or mulch needed for any area depth.
Calculate square footage, boxes needed, and total cost for hardwood, laminate, vinyl, tile, or carpet.
Calculate posts, rails, boards, and materials needed for privacy, picket, split-rail, or vinyl fencing.
A standard gallon of paint covers about 350–400 square feet per coat. For a 12×14 ft room with 8 ft ceilings: wall area ≈ 416 sq ft (minus doors/windows ≈ 50 sq ft = 366 sq ft). With 2 coats: 366 × 2 = 732 sq ft ÷ 350 = ~2.1 gallons. Always buy slightly more than your estimate — you want consistent dye lots for touch-ups.
Volume = Length × Width × Thickness (all in feet). Divide by 27 to get cubic yards. Add 10% for waste. Example: 10 × 10 ft patio, 4 inches thick = 10 × 10 × (4/12) = 33.3 cu ft = 1.23 cu yards. You'd order 1.4 cu yards. One 80 lb bag of concrete mix = 0.60 cu ft, so you'd need about 56 bags.
Standard driveway gravel depth is 4 inches. For a 100 × 12 ft driveway at 4 inches deep: Volume = 100 × 12 × (4/12) = 400 cu ft = 14.8 cu yards. Gravel weighs ~1.4 tons per cu yard = ~20.7 tons. A typical bulk delivery truck carries 10–14 tons, so you'd need 2 loads. Our Gravel Calculator handles all materials and depths.
Measure length × width to get base square footage. Add 10% for waste (15% for diagonal installations or rooms with odd angles). Divide total sq ft by the box coverage to get number of boxes — always round up. Example: 200 sq ft room + 10% = 220 sq ft. If boxes cover 20 sq ft each: 220 ÷ 20 = 11 boxes.
Posts are typically spaced 6–8 feet apart. For 200 linear feet at 8-foot spacing: 200 ÷ 8 = 25 spans + 1 end post = 26 posts. For corners and gates, add extra posts. Each post needs 2 bags of concrete (80 lb). For a 6-foot privacy fence: each span needs 2 horizontal rails and approximately 17–18 boards (1×6 boards at 5.5 inches wide).