Concrete Calculator

Overview

Converts slab dimensions and thickness into ready-mix yards and 80-lb bag yield, plus planning quantities for forms and reinforcement.

Assumptions

• The slab is rectangular with uniform thickness.
• An 80-lb bag is modeled as 0.6 cu ft; base depth is fixed at 4 in.

Worked example

A 10 × 10 ft slab at 4 in is 33.33 cu ft = 1.23 cu yd; the bag equivalent is ceil(33.33 ÷ 0.6) = 56 bags.

Common mistakes

• Ordering bags without considering mixing and placement time.
• Assuming this material list is a structural slab design.

Limitations

No strength, joint layout, reinforcement, frost, or site-load design is performed.

Safety and local requirements

Wet concrete can burn skin and injure eyes. Use PPE; check local requirements for footings, setbacks, and runoff.

Sources

• OSHA — Landscaping and Horticulture
• International Code Council — code reference background