Concrete Slab / Foundation Calculator

Methodology

Volume = W × L × thickness ÷ 27 = cubic yards, plus 10% for over-excavation and spillage. One 80 lb bag yields about 0.6 cu ft. Ready-mix costs $125–$175/yd³ delivered, and an installed 4″ slab runs $6–$12/sq ft (Estimators.us, Concrete Slab Cost 2026, as of 2026-10-14). Small orders below the truck minimum often pay a $50–$100 short-load fee (DesignAndBids, as of 2026-10-14). The installed range is for 4″ slabs, so thicker slabs cost more.

Last reviewed: 2026-10-14. Prices are national planning ranges; get local quotes.