Construction & DIY Calculators

Buying the right amount of material is the difference between a smooth weekend project and a second trip to the store in the middle of a pour. These construction and DIY calculators turn your measurements into a shopping list: bags of concrete, gallons of paint, boxes of tile or flooring, sheets of drywall, deck boards, fence posts and cubic yards of mulch or gravel.

Every calculator works the same way. Enter your measurements in feet and inches, or switch to metric. The calculator works out the area or volume, adds a sensible waste allowance for cuts, spills and breakage, and rounds up to whole units, because you can’t buy 41.3 bags. The waste percentage is always editable, so you can tighten it for a simple rectangle or raise it for a room full of corners.

Below each calculator you’ll find the formula written out, a worked example with real numbers, common mistakes to avoid, and the sources behind any coverage or yield figures, such as manufacturer data sheets for bag yields. That way you can check the math on site with a tape measure and a phone, and know where the numbers come from.

The calculators are grouped by trade below: concrete and masonry, painting, landscaping, flooring, walls, and outdoor projects. If a project spans several of them, such as a fence with concrete-set posts and gravel at the base, each page links to the related calculators you’ll need next.