Every project starts with the right number.
Pick a tool off the wall, give it your measurements, and walk out with a buy list — gallons, boxes, cubic yards — waste margin already figured in.
Paint
Gallons and quarts for any room
Answer in gallonsAC Size
BTUs and tonnage for the space
Answer in BTU/hrFlooring
Boxes with waste built in
Answer in boxesMulch & Soil
Cubic yards and bag counts
Answer in yardsGravel
Yards and tons delivered right
Answer in tonsWallpaper
Rolls with pattern waste
Answer in rollsFence
Posts, rails, and picket runs
Answer in postsDeck Boards
Boards, screws, linear feet
Answer in boardsMeasure. Hang. Buy.
Most calculators stop at an area — "you need 180 square feet." That's not what the shelf sells. Every PlankMath tool converts your room into purchase units: coats and coverage into gallons, square footage plus waste into sealed boxes, depth into cubic yards and bag counts. The assumptions aren't buried in code; they're printed on the tag where you can change them.
- Buy-lists, not arithmetic — output in the units stores actually sell.
- Assumptions on the counter — adjust coats, waste %, and coverage rates yourself.
- Answer first — the number lands as you type; the how-it-works text is below it.