Methodology

How our calculator estimates are built.

Every calculator starts with a simple measurable quantity, applies a visible formula, and keeps assumptions separate from the final result so the estimate can be checked before materials are ordered.

Core estimating process

  1. Measure the project shape. Calculators use dimensions such as length, width, thickness, depth, diameter, rise, run, or area.
  2. Normalize units. Inches are converted to feet when volume requires matching units. Square feet, cubic feet, cubic yards, tons, and roofing squares are shown separately where relevant.
  3. Apply the formula. The formula is displayed on each calculator page, along with a plain-English explanation of what the formula means.
  4. Add waste after the base quantity. Waste is applied after the base area or volume is calculated so users can see how ordering buffers affect the result.

Concrete estimates

Concrete tools calculate cubic feet first, then divide by 27 for cubic yards. Bag estimates use common planning yields such as 80 lb bags at about 0.60 cubic feet, with results rounded up to whole bags.

Roofing estimates

Roofing tools convert rise and run into pitch, degrees, slope percentage, and pitch multiplier. Roof area tools apply the pitch multiplier to flat footprint area before waste or material units are added.

Landscaping estimates

Mulch and gravel tools convert area and depth into cubic feet and cubic yards. Gravel tonnage uses density assumptions that should be checked against the supplier's product data before ordering.

Area estimates

Area tools split projects into simple shapes such as rectangles, triangles, and circles. The total square footage can then be used as the starting point for material-specific calculators.

What users should verify locally