Home & Yard Calculators

About these home & yard calculators

Bulk materials are priced to punish a second trip. Mulch and gravel come by the cubic yard, which is nine cubic feet more than most people picture; a yard of mulch covers about 100 square feet at three inches deep and no more. Sod arrives on pallets of roughly 450 square feet. Wallpaper comes in rolls whose usable length depends on your pattern repeat, not on the label. Getting the unit conversion right is most of the job.

The second half is waste, and it is not optional. Pavers need cuts at every edge, so a ten percent allowance is standard. Deck boards need the same. Wallpaper needs whole strips even where a window interrupts the wall, which is why the strip method used here gives a different — and more reliable — answer than multiplying square footage. Paint is the exception: the usual failure is buying too much, because 350 square feet per gallon is a genuinely achievable coverage on a sealed wall.

Depth is the input people get wrong most often. Three inches of mulch suppresses weeds and holds moisture; two inches does neither, and five inches suffocates roots and holds damp against stems. Gravel wants four inches for a path and more under pavers. Topsoil for a new bed wants six. Each calculator defaults to the depth that actually works for that material rather than the one that makes the number look small.

Everything here is an estimate for planning and shopping. Ground is rarely flat, walls are rarely square, and a slope or a bow adds material that no formula can see from a length and a width. Measure twice, run the numbers, and buy a little over on anything that comes in a batch — wallpaper especially, where a second order may not match the first.