Concrete Calculators
Every concrete project starts with a volume calculation. Whether you're pouring a driveway slab, setting fence posts, or building a foundation, knowing the exact cubic yards prevents costly over-ordering and dangerous shortages.
Our concrete calculators cover the full range of residential and light commercial projects — from simple rectangular slabs to cylindrical column piers and complex stair geometry. All include configurable waste factors because real-world pours always consume more than pure geometry predicts.
All Concrete Tools
Concrete Basics
- 1 cubic yard = 27 cubic feet = 81 square feet at 4" thick
- 1 cubic yard weighs approximately 4,050 lbs
- 80 lb bag yields 0.6 cubic feet (45 bags per cubic yard)
- Ready-mix minimum is typically 1 cubic yard ($125-175/yard + delivery)
- Standard residential slab thickness: 4" (patios, walkways) to 6" (driveways, garages)
When to Use Bags vs. Ready-Mix
For projects under 0.75 cubic yards (about 20 cubic feet), bags are more economical. Above that threshold, ready-mix delivery saves significant time and produces more consistent results. The crossover cost point is typically around $150-200 in materials for bags vs. a single-yard delivery fee.
Disclaimer
These calculators provide estimates only. Actual material requirements vary based on site conditions, mix design, and installation methods. Always verify quantities with your supplier before ordering. For structural concrete (foundations, load-bearing walls), consult a licensed structural engineer. See our Terms of Use.