16 by 16 ft slab at 8 inches
Calculate the requirements for a 16 ft by 16 ft residential concrete slab at 8 inches thick with #4 rebar at 18 inches spacing. Ensure compliance with IRC R506 standards.
Formula SSC-2026.1
Formula SSC-2026.1 · 4,000 PSI
Order volume
7.77 yd³
5.939 m³ placed+waste
Order weight
31,460 lb
14,270 kg
80 lb bags
350
9 pallets at 42 bags
60 lb bags
467
0.45 ft³ yield each
Rebar
480.00 ft
30 × 20 ft · 30 × 6 m · 353 lb
Ready-mix vs bags
$1,281.70
Truck $1,281.70 · 80 lb bags $2,362.50
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 | 7.06 yd³ | 10% | 7.77 yd³ / 5.939 m³ | USD | $1,281.70 | 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 | 317.8 bags | 10% | 350 bags | USD | $2,362.50 | Source Spec Material / Tool |
| 60 lb pre-mix bags | 423.7 bags | 10% | 467 bags | USD | $2,521.80 | Source Spec Material / Tool |
| #4 rebar sticks, 20 ft | 30 sticks | 10% | 33 sticks / 30 × 6 m | USD | $462.00 | Source Spec Material / Tool |
| Rebar chairs | 121 crossings | 10% | 134 chairs | USD | $37.52 | Source Spec Material / Tool |
| Tie wire rolls | 121 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
$1,281.70
0.78 nominal 10 yd³ loads · 1 to order
80 lb bags
$2,362.50
60 lb alternative $2,521.80 · delivery weight 31,460 lb
| Thickness | Order yd³ | Order m³ | 80 lb bags | Rebar ft | Ready-mix | 80 lb cost |
|---|---|---|---|---|---|---|
| 4 in | 5.11 | 3.904 | 230 | 528 | $842.52 | $1,552.50 |
| 5 in | 5.77 | 4.413 | 260 | 528 | $952.31 | $1,755.00 |
| 6 in | 6.44 | 4.921 | 290 | 528 | $1,062.11 | $1,957.50 |
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: 16 by 16 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 is designed to help you estimate the requirements for a residential concrete slab measuring 16 ft by 16 ft and 8 inches thick. The slab will incorporate #4 rebar placed at 18-inch intervals to enhance structural integrity.
Please note that soil design considerations are excluded from this calculation. It is essential to consult a qualified engineer for soil analysis and site-specific recommendations.
Code reference
IRC R506 - Concrete Floors on Ground
Field questions
- What is the purpose of using #4 rebar in the slab?
- The #4 rebar provides tensile strength to the concrete slab, helping to prevent cracking and improve load-bearing capacity.
- Is soil design included in this calculation?
- No, soil design is excluded from this calculation. It is recommended to consult with a qualified engineer for soil analysis.
- What thickness is recommended for a residential slab?
- For a typical residential slab, a thickness of 8 inches is common, but this can vary based on specific load requirements and local building codes.