12 by 16 ft slab at 6 inches
Calculate the specifications for a residential slab measuring 12 ft by 16 ft at 6 in thickness with #4 bars at 18 in spacing. Ensure compliance with IRC R506 while excluding soil design considerations.
Formula SSC-2026.1
Formula SSC-2026.1 · 4,000 PSI
Order volume
4.97 yd³
3.800 m³ placed+waste
Order weight
20,130 lb
9,131 kg
80 lb bags
224
6 pallets at 42 bags
60 lb bags
299
0.45 ft³ yield each
Rebar
388.00 ft
26 × 20 ft · 26 × 6 m · 285 lb
Ready-mix vs bags
$820.11
Truck $820.11 · 80 lb bags $1,512.00
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 | 4.52 yd³ | 10% | 4.97 yd³ / 3.800 m³ | USD | $820.11 | Source Spec Material / Tool |
| Short-load fee | Full load | — | 1 truck @ 10 yd³ | USD | $0.00 | Source Spec Material / Tool |
| 80 lb pre-mix bags | 203.3 bags | 10% | 224 bags | USD | $1,512.00 | Source Spec Material / Tool |
| 60 lb pre-mix bags | 271.1 bags | 10% | 299 bags | USD | $1,614.60 | Source Spec Material / Tool |
| #4 rebar sticks, 20 ft | 26 sticks | 10% | 29 sticks / 26 × 6 m | USD | $406.00 | Source Spec Material / Tool |
| Rebar chairs | 99 crossings | 10% | 109 chairs | USD | $30.52 | Source Spec Material / Tool |
| Tie wire rolls | 99 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
$820.11
0.50 nominal 10 yd³ loads · 1 to order
80 lb bags
$1,512.00
60 lb alternative $1,614.60 · delivery weight 20,130 lb
| Thickness | Order yd³ | Order m³ | 80 lb bags | Rebar ft | Ready-mix | 80 lb cost |
|---|---|---|---|---|---|---|
| 4 in | 4.02 | 3.073 | 181 | 427 | $663.26 | $1,221.75 |
| 5 in | 4.50 | 3.437 | 203 | 427 | $741.69 | $1,370.25 |
| 6 in | 4.97 | 3.800 | 224 | 427 | $820.11 | $1,512.00 |
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: 12 by 16 ft slab at 6 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 helps you determine the necessary specifications for a residential concrete slab measuring 12 ft by 16 ft and 6 inches thick. The design includes #4 rebar spaced at 18 inches apart, ensuring structural integrity.
Note that soil design is not included in this calculation, and it is essential to consult local building codes and a qualified engineer for site-specific requirements.
Code reference
IRC R506 - Concrete Floors on Ground
Field questions
- What is the purpose of rebar in a concrete slab?
- Rebar is used to reinforce concrete, providing tensile strength and helping to prevent cracking and structural failure.
- Why is soil design excluded from this calculation?
- Soil design is site-specific and depends on various factors such as soil type, moisture content, and load-bearing capacity, which must be evaluated by a qualified professional.
- What does IRC R506 cover?
- IRC R506 provides guidelines for the design and construction of concrete floors on the ground, including thickness, reinforcement, and curing requirements.