Plain-English guides to help you plan, save, and decide with confidence.
Multiply length x width x depth (in feet) and divide by 27 to get cubic yards. See the quick formula, a size reference table, and how many bags that equals.
Read →You need about 45 80-lb bags or 60 60-lb bags to make one cubic yard of concrete. See the full comparison table, cost breakdown, and when to choose bags vs ready-mix.
Read →Most residential slabs are 4 inches thick. Driveways are 4 to 6 inches; garage floors 4 to 6; heavy-equipment pads 6 to 8. See the full table by use case.
Read →Installed concrete slabs average $6 to $12 per square foot in 2025, or $1,300 to $5,000 for most residential projects. See cost by size, thickness, and region.
Read →Plan for 4 inches of compacted gravel under most residential slabs. Multiply length x width x 0.333 ft and divide by 27 for cubic yards. See the coverage table.
Read →For rectangular footings multiply length x width x depth in feet and divide by 27. For round sonotubes use pi x r^2 x depth. See worked examples and a bag count table.
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