Concrete Patio Calculator
A 16×12 ft patio at 4 inches thick needs about 2.4 cubic yards of concrete — roughly 107 bags of 80-lb mix with waste. Enter your dimensions below for the exact volume, bag count, and cost estimate.
Pro Tips
- →Patios typically need 4 inches of concrete thickness
- →Add a 2% slope away from your house for drainage
- →Consider decorative finishes like stamping or staining
- →Include 10% extra concrete for waste
- →Compact the gravel base thoroughly before pouring
Includes 10% waste factor
That's typically a professional pour. See costs ↓
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Cost Estimate
Estimated material costs for your project
Recommendation: Ready-Mix Concrete
For projects over 1 cubic yard, ready-mix is typically more economical and easier to work with.
118 bags × 80lb
2.61 cubic yards + delivery
192 sq ft × $3.00–$8.00/sq ft
Prices vary by location and time. Contact local suppliers for accurate quotes.
For general step-by-step instructions, read our complete Patio Thickness and Patio Guide.
Patio Size and Concrete Volume
Most residential patios fall between 150 and 400 square feet — enough for an outdoor dining set, lounge chairs, and a grill with room to move. Concrete patio thickness is always 4 inches for foot-traffic surfaces. Increase to 5 inches only if vehicles, golf carts, or extremely heavy equipment will load the surface.
| Patio Size | Sq Ft | Cubic Yards (4 in) | 80-lb Bags (incl. 10% waste) |
|---|---|---|---|
| 10×10 ft | 100 | 1.23 cu yd | 55 bags |
| 12×12 ft | 144 | 1.78 cu yd | 80 bags |
| 16×12 ft | 192 | 2.37 cu yd | 107 bags |
| 16×20 ft | 320 | 3.95 cu yd | 178 bags |
| 20×20 ft | 400 | 4.94 cu yd | 222 bags |
Patios over 2 cubic yards are typically more cost-effective with ready-mix delivery at $130–$170 per cubic yard. For a 16×20 ft patio (4 cu yd), bagged concrete requires handling nearly 180 bags — most homeowners opt for ready-mix at that scale.
Slope and Drainage
Every concrete patio needs a 1/4-inch-per-foot slope away from the house — about a 2% grade. This seems minimal but is critical: water pooling against a foundation creates long-term moisture problems. Mark the high point at the house wall and the low point at the patio's outer edge before setting forms.
Isolation joint: Always install a 1/2-inch foam expansion joint strip between the patio and the house wall. Without it, the patio and foundation expand and contract at different rates, cracking both the patio and potentially the foundation wall.
Control Joints and Crack Prevention
Concrete patios need control joints every 8–10 feet in both directions. For a 16×20 ft patio, place joints at 8 feet from one end (making 8 ft and 12 ft panels lengthwise) and at 10 feet across. Joints should be cut to 1/4 of the slab depth — 1 inch deep for a 4-inch slab. Per ACI 302.1R (Guide for Concrete Floor and Slab Construction), joint spacing in feet should not exceed 2–3 times the slab thickness in inches — so a 4-inch patio slab should have joints no more than 8–12 feet apart.
Finish Options and Added Cost
| Finish Type | Added Cost | Maintenance |
|---|---|---|
| Broom finish | $0 (standard) | Low |
| Exposed aggregate | $2–4/sq ft | Low |
| Stamped concrete | $8–18/sq ft | Medium |
| Acid stain (on cured slab) | $2–4/sq ft | Medium |
| Integral color | $2–4/sq ft | Low |
For step-by-step pour guidance, see How to Pour Concrete. To estimate total project cost with labor, use our Concrete Patio Cost Calculator.