Concrete Slab Calculator: Estimate Cubic Yards, Tons & Bags (2026 Cost Guide)
Poured concrete for patios, shed pads, sidewalks and hot tub slabs — ready-mix truck or bagged mix.
Most residential slabs are 4 inches thick; driveways and hot tub pads are 5–6 inches. Concrete is sold by the cubic yard from ready-mix suppliers, or in 40, 60 and 80 lb bags at the hardware store. An 80 lb bag yields about 0.6 cu. ft, so one cubic yard takes 45 bags — beyond about 1 yard, a ready-mix truck (even with a short-load fee) is usually cheaper and much faster.
1Measure your area
2Prices (optional)
+ $150 typical delivery
Your Concrete Slab estimate
Total volume
2.72 cu. yd
Bags needed
123
Estimated weight
5.5 tons
Bulk order
2.75 cu. yd
- Bulk (2.75 yd + delivery)Best value$618
$468 material + $150 delivery
- Bagged (123 × 80 lb bag (0.60 cu. ft))$797
$6.48 per bag
Bulk delivery saves about $180. Prices are US averages — enter your local quotes above.
Can my truck haul it?
- Mid-size pickup (~1,000 lbs)11 trips
- Half-ton pickup (F-150 / Silverado 1500) (~1,500 lbs)8 trips
- 3/4-ton pickup (2500 series) (~2,500 lbs)5 trips
- 1-ton pickup (3500 series) (~4,000 lbs)3 trips
Material shopping list
| Concrete Slab — bulk≈ 5.5 tons · $618 delivered | 2.75 cu. yd |
| Concrete Slab — or bagged (80 lb bag (0.60 cu. ft))$797 at $6.48/bag | 123 bags |
| Coverage4" deep · 10% overage included | 200 sq. ft |
Prices are estimates. Confirm bag yield (cu. ft) on the package before buying.
How much concrete slab do I need? Quick-reference table
Pre-calculated amounts for common project sizes, including a 10% overage. Bags are based on the 80 lb bag (0.60 cu. ft); weight uses 4,050 lbs per cubic yard.
| Area | Depth | Cubic yards | Cubic feet | Bags | Weight |
|---|---|---|---|---|---|
| 10×10 ft (100 sq. ft) | 4" | 1.36 | 36.7 | 62 | 2.75 tons |
| 10×10 ft (100 sq. ft) | 5" | 1.7 | 45.8 | 77 | 3.44 tons |
| 10×10 ft (100 sq. ft) | 6" | 2.04 | 55 | 92 | 4.13 tons |
| 12×12 ft (144 sq. ft) | 4" | 1.96 | 52.8 | 88 | 3.96 tons |
| 12×12 ft (144 sq. ft) | 5" | 2.44 | 66 | 110 | 4.95 tons |
| 12×12 ft (144 sq. ft) | 6" | 2.93 | 79.2 | 132 | 5.94 tons |
| 20×20 ft (400 sq. ft) | 4" | 5.43 | 146.7 | 245 | 11 tons |
| 20×20 ft (400 sq. ft) | 5" | 6.79 | 183.3 | 306 | 13.75 tons |
| 20×20 ft (400 sq. ft) | 6" | 8.15 | 220 | 367 | 16.5 tons |
How much area does a cubic yard of concrete slab cover?
| Depth | 1 cu. yd covers | 1 ton covers | 1 bag covers |
|---|---|---|---|
| 1" | 324 sq. ft | 160 sq. ft | 7.2 sq. ft |
| 2" | 162 sq. ft | 80 sq. ft | 3.6 sq. ft |
| 3" | 108 sq. ft | 53 sq. ft | 2.4 sq. ft |
| 4" | 81 sq. ft | 40 sq. ft | 1.8 sq. ft |
| 6" | 54 sq. ft | 27 sq. ft | 1.2 sq. ft |
| 8" | 41 sq. ft | 20 sq. ft | 0.9 sq. ft |
The concrete slab formula, step by step
This calculator uses the standard US bulk-material formula:Cubic Yards = (Area in sq. ft × (Depth in inches ÷ 12)) ÷ 27. Here's a worked example for a 12 × 12 ft area at 4 inches deep:
- Measure the area. Multiply length × width in feet to get square feet. Break irregular shapes into rectangles and add them.
- Convert depth to feet. Divide the depth in inches by 12. A 4" layer is 0.333 ft.
- Calculate cubic feet and yards. Multiply square feet × depth in feet for cubic feet, then divide by 27 for cubic yards.
- Add a waste factor. Multiply by 1.10 to add 10% for settling, compaction and spillage.
- Convert to bags and tons. Divide cubic feet by 0.6 for 80 lb bag (0.60 cu. ft), and multiply cubic yards by 2.03 for tons.
Result: 144 sq. ft × 0.333 ft = 48cu. ft ÷ 27 = 1.78 cubic yards. With 10% extra that's 1.96 cu. yd — about 88 bags or 3.96 tons.
Concrete Slab cost guide (2026)
- Bulk:$140–$210 per cubic yard (US average ≈ $170), plus about $150 delivery.
- Bagged:80 lb bag (0.60 cu. ft) ≈ $6.48 each — 45 bags per yard, or about $292 per cubic yard.
- Weight: 4,050 lbs per cubic yard (2.03tons). A half-ton pickup can safely carry about 0.37 cu. yd per trip.
Pro tips for installing concrete slab
- Place 4 inches of compacted gravel base under the slab to prevent cracking from frost heave and settling.
- Order 5–10% extra: uneven subgrade, form bulges and spillage add up fast.
- Add control joints every 8–12 ft (about 2–3× the slab thickness in feet) to control cracking.
- Mixing 40+ bags by hand is a long day — rent a mixer or schedule a ready-mix truck.
Common uses
- Patios, walkways and sidewalks (4")
- Shed, garage and hot tub pads (4–6")
- Driveways and RV pads (5–6" with rebar)
Concrete Slab FAQ
How many 80 lb bags of concrete are in a yard?
One 80 lb bag yields about 0.6 cubic feet, so a cubic yard (27 cu. ft) takes 45 bags. With 60 lb bags (0.45 cu. ft) it takes 60 bags.
How much concrete do I need for a 10×10 slab?
A 10×10 ft slab at 4 inches thick is 1.23 cubic yards. With 10% extra, order 1.36 yards from a ready-mix supplier or buy about 62 bags of 80 lb mix.
How thick should a concrete patio be?
4 inches is standard for patios and walkways. Use 5–6 inches with rebar or wire mesh for hot tubs, vehicle parking or heavy equipment.
What is a short-load fee for ready-mix concrete?
Most ready-mix plants charge an extra $50–$200 for orders under 3–5 cubic yards. Even with that fee, a truck is usually cheaper than bags once you need more than about 1–1.5 yards.