TRANSPARENT METHODS
How Our Construction Calculators Work
Measured geometry, explicit conversions and product data you control. These tools calculate material estimates; they do not choose a construction design.
Reviewed: October 2026
Concrete volume & conversion
Rectangle: V = L × W × D × quantity. Cylinder: V = π × (diameter / 2)² × depth × quantity. Order = net × (1 + waste / 100).
Dimensions describe the project, not its suitability. Rectangular walls and trenches use the same prism formula. Constant dimensions and uniform depth are assumed. One cubic yard is 27 cubic feet.
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Concrete bags & yields
Exact bags = order volume / yield per bag. Whole bags = round up(exact bags). Unused capacity = whole bags × yield − order volume.
Reference presets come from Concrete Mix No. 1101, not all products. Verify packaging and override the yield. Metric packaging uses your own product yield; weight alone does not determine yield.
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Concrete blocks
Net wall area = gross wall area − openings. Exact blocks = net area / nominal face area. Order blocks = round up(exact blocks × (1 + waste / 100)).
Use nominal modular face dimensions, including the joint allowance, rather than actual face dimensions. Area-based counts do not plan bond patterns, cuts or corner units. Optional fill uses user-supplied void volume per installed whole-block equivalent, not purchased spare blocks.
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Post-hole quantities
Per-hole concrete = (hole cross-sectional area − post cross-sectional area) × (hole depth − gravel base depth). Total = per-hole × number of holes.
Round holes, centered round or square posts and constant cross-sections are assumed. Post displacement spans the concrete depth. Gravel depth is optional and user-entered. No dimensions or frost depths are selected by the tool.
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Concrete material costs
Material cost = order volume × entered price in matching volume units. Total = material cost + delivery + other fixed fees.
Prices and fees are supplied by you. USD is a display convention, not a pricing database. Labor, reinforcing, base, excavation, pump rental and tax are not automatically included. Slab cost per area uses the total entered estimate divided by slab area.
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Paint coverage
Room walls = 2 × (length + width) × height. Paintable area = gross walls − openings + optional ceiling. Paint = paintable area × coats / coverage.
Coverage is required from your product label and is per coat. Surface, application and product can change coverage. No universal coverage is prefilled. Room ceiling uses the same entered coverage and coat count; run separate estimates for different products or coats. Optional container counts round upward.
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Tile quantities
Exact tiles = project area / tile face area. Order tiles = round up(exact tiles × (1 + waste / 100)). Boxes = round up(order area / entered box coverage).
Area-based estimates are not a cut/layout plan. No grout spacing or overlap is deducted. Box coverage is supplied by the user; tile and box counts are separate purchase options. Shower walls use three entered wall widths; floor and walls can be selected separately.
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Rubber mulch volume
Rectangle area = length × width. Circle area = π × (diameter / 2)². Volume = area × entered depth. Packages = round up(volume / package yield).
Uniform user-entered depth is assumed. Packaging yields must correspond to your product. This tool does not determine fall protection or playground safety depth.
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Board feet
Board feet = thickness (in) × width (in) × length (ft) / 12 × quantity.
One board foot is 144 cubic inches. Enter the dimensions you intend to measure; the tool does not substitute nominal or finished sizes. Quarter notation such as 5/4 means 1.25 inches. This is not a log-yield estimate.
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Precision and purchase rounding
Calculations keep internal precision. Results are formatted for readability; very small nonzero quantities use scientific notation rather than displaying as zero. Bags, blocks, tiles, containers and packages round upward, while continuous volume remains unrounded internally. Area-based material counts do not replace layout plans.
Prices, packaging and coverage change by supplier and product. Always check your measurements, packaging and quoted assumptions before ordering.