Calculate exactly how much concrete you need for slabs, footings, columns, and stairs. Get instant results in cubic yards, number of pre-mixed bags (40, 60, and 80 lb), total weight, and estimated cost. Free to use — no signup required.
See our concrete coverage table for quick volume lookups. Planning a patio? See our full concrete patio cost guide for 2026 pricing.
Common slab sizes at standard depth (no waste factor).
| Size | Depth | Cubic Yards |
|---|---|---|
| 4 × 4 ft | 4" | 0.20 |
| 8 × 10 ft | 4" | 0.99 |
| 10 × 10 ft | 4" | 1.23 |
| 12 × 12 ft | 4" | 1.78 |
| 20 × 20 ft | 4" | 4.94 |
| 10 × 10 ft | 6" | 1.85 |
Planning a 10×10 foot patio slab at 4 inches thick? You would need approximately 1.24 cubic yards of concrete. That works out to about 56 bags of 80-lb mix, 75 bags of 60-lb mix, or 112 bags of 40-lb mix. At a typical ready-mix price of $125–$175 per cubic yard, expect to spend roughly $155–$217 on materials. For anything over 1 cubic yard, calling your local batch plant for ready-mix delivery is usually cheaper and faster than mixing bags by hand.
| Project | Volume |
|---|---|
| 4" slab, 10×10 ft | 1.24 yd³ |
| 4" slab, 12×12 ft | 1.78 yd³ |
| 6" slab, 10×10 ft | 1.85 yd³ |
| 4" walkway, 3×20 ft | 0.74 yd³ |
| 12" tube, 4 ft tall | 0.12 yd³ |
| Footing, 1×1×20 ft | 0.74 yd³ |
For a 4-inch thick 10×10 slab, you need approximately 56 bags of 80-lb concrete mix, 75 bags of 60-lb mix, or 112 bags of 40-lb mix. That's about 1.24 cubic yards total.
Approximately 4,050 pounds, or roughly 2 tons.
For jobs under 1 cubic yard, bags are practical and cost-effective. Over 1 yard, ready-mix delivery from a local batch plant is usually cheaper and saves significant labor.
Add 10% to your calculated amount to account for spillage, uneven subgrade, and form movement. Coming up short mid-pour is far more expensive than having a little extra.
4 inches is standard for patios, walkways, and most residential slabs. Use 5–6 inches for driveways and garage floors that support vehicle weight.
Approximately 45 bags. Each 80-lb bag yields about 0.6 cubic feet, and there are 27 cubic feet in a cubic yard.
Pouring the patio yourself? See our concrete patio guide for forming, mixing, finishing, and curing step by step.
Typical Results
💡 If your result seems too high, check that you entered thickness in inches, not feet.
Common Mistakes