10 by 12 ft slab at 8 inches
Calculate the specifications for a 10 ft by 12 ft residential slab at 8 in thickness with #4 bars at 18 in spacing. Ensure compliance with IRC R506 standards.
Formula SSC-2026.1
Formula SSC-2026.1 · 4,000 PSI
Order volume
3.80 yd³
2.907 m³ placed+waste
Order weight
15,400 lb
6,985 kg
80 lb bags
172
5 pallets at 42 bags
60 lb bags
229
0.45 ft³ yield each
Rebar
262.00 ft
22 × 20 ft · 22 × 6 m · 193 lb
Ready-mix vs bags
$752.41
Truck $752.41 · 80 lb bags $1,161.00
Grid lines are equalized so the drawing stays readable. The order count uses on-center spacing with a bar at each end of the layout, then holds concrete cover in the field.
| Item | Net | Waste | Order | Unit price | Line total | Source Spec Material / Tool |
|---|---|---|---|---|---|---|
| Ready-mix concrete | 3.46 yd³ | 10% | 3.80 yd³ / 2.907 m³ | USD | $627.41 | Source Spec Material / Tool |
| Short-load fee | Under 4 yd³ | — | 1 truck @ 10 yd³ | USD | $125.00 | Source Spec Material / Tool |
| 80 lb pre-mix bags | 155.6 bags | 10% | 172 bags | USD | $1,161.00 | Source Spec Material / Tool |
| 60 lb pre-mix bags | 207.4 bags | 10% | 229 bags | USD | $1,236.60 | Source Spec Material / Tool |
| #4 rebar sticks, 20 ft | 22 sticks | 10% | 25 sticks / 22 × 6 m | USD | $350.00 | Source Spec Material / Tool |
| Rebar chairs | 63 crossings | 10% | 70 chairs | USD | $19.60 | Source Spec Material / Tool |
| Tie wire rolls | 63 ties | 10% | 1 rolls | USD | $8.00 | Source Spec Material / Tool |
Source links open a product search on the Amazon storefront for the selected currency. SiteSpecCalc may earn a commission. The link does not change the quantities above.
Ready-mix truck
$752.41
0.38 nominal 10 yd³ loads · 1 to order
80 lb bags
$1,161.00
60 lb alternative $1,236.60 · delivery weight 15,400 lb
| Thickness | Order yd³ | Order m³ | 80 lb bags | Rebar ft | Ready-mix | 80 lb cost |
|---|---|---|---|---|---|---|
| 4 in | 2.72 | 2.077 | 123 | 288 | $573.15 | $830.25 |
| 5 in | 2.99 | 2.284 | 135 | 288 | $617.96 | $911.25 |
| 6 in | 3.26 | 2.492 | 147 | 288 | $662.78 | $992.25 |
Show the deterministic formula
Slab ft³ = L × W × thickness ÷ 12. Thickened-edge extra = footing band × (footing depth − slab thickness), with corner squares counted once.
yd³ = ft³ ÷ 27. m³ = ft³ × 0.0283168. Weight uses 150 lb/ft³, then the header converts that pound total at 1 lb = 0.45359237 kg. 80 lb bags yield 0.6 ft³ and 60 lb bags yield 0.45 ft³. Currency changes the price labels only.
Bars across a span = floor(span ÷ spacing) + 1. Order sticks = that count, plus 10, 5, or 15 percent waste, cut from 20 ft and 6 m stock. Chairs = one per grid intersection.
Contractor sign-off
Project: 10 by 12 ft slab at 8 inches
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This sheet is an estimate for ordering and layout discussion. It is not a sealed design. Confirm the quantities with a licensed local professional and the authority having jurisdiction before you buy or build.
Engineering notes
This calculator provides the necessary specifications for designing a residential slab measuring 10 ft by 12 ft with a thickness of 8 inches. Reinforcement is achieved using #4 bars placed at 18 inches on center, ensuring structural integrity.
Please note that soil design considerations are excluded from this calculation. It is essential to consult a qualified professional for soil evaluation and compliance with local building codes.
Code reference
IRC R506
Field questions
- What is the purpose of using #4 bars in the slab?
- The use of #4 bars provides reinforcement to the concrete slab, helping to control cracking and improve load-bearing capacity.
- Why is soil design excluded from this calculation?
- Soil design is excluded because it requires site-specific evaluation and testing to determine the appropriate foundation design based on soil conditions.
- What does IRC R506 cover?
- IRC R506 covers the requirements for concrete slabs on grade, including design, construction, and reinforcement specifications.
- What are the dimensions of the slab in this design?
- The slab dimensions are 10 feet by 12 feet, with a thickness of 8 inches.
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