Home & Construction calculators

Real coverage is never perfectly uniform: uneven ground, waste from cutting, and spillage all consume more material than the flat geometric calculation suggests. Rounding up avoids a second supply trip. That trip usually costs more in time than the extra material costs in money.

10% is a common baseline for a straightforward rectangular room in a simple grid layout. Diagonal layouts, rooms with lots of cuts around fixtures, or a pattern that requires matching increase that. 15-20% is common for more complex jobs.

A steeper roof has more actual surface area than its flat footprint suggests, because the surface is tilted , not horizontal. The pitch multiplier scales the flat footprint area up to the true sloped surface area material actually has to cover.

A unit specific to roofing equal to 100 square feet of roof surface. Materials like shingles and underlayment are typically priced and packaged per square, which is why roofing estimates are usually expressed that way instead of in raw square footage.

The base calculation is the geometric quantity needed to exactly cover the area, always add your own waste margin, since actual waste depends heavily on the specific layout, cut complexity and your own installation experience.

Saw kerf removes a small sliver of material with every cut, and real pieces rarely nest perfectly against a sheet's edges the way a pure area calculation assumes. A 10 to 15% allowance on top of the exact geometric area covers both without forcing a mid-project supply run.

No, the opposite: a pilot hole sized for the screw's root diameter gives the threads material to bite into as they're driven. Too large a pilot hole strips the threads' grip and weakens the joint, while too small a hole risks splitting the wood, especially near an edge.

Hardwood is denser and less able to compress or flex around a screw's threads without splitting. A slightly larger pilot hole relieves some of that stress before the screw is driven, at the cost of very slightly less thread grip than the same screw would get in softwood.

Order about 10% more than the area, and up to 15% for diagonal layouts, tile with patterns or rooms with many corners.

Find the wall area, subtract doors and windows, divide by the coverage on the can, about 350 square feet per gallon, and multiply by the coats.

27, since a yard is three feet on each side, which is why bulk mulch and gravel quantities are converted from feet.