16 by 24 ft slab at 8 inches
Calculate the requirements for a 16 ft by 24 ft residential concrete slab with #4 rebar at 18 in spacing. Ensure compliance with IRC R506 for slab design.
Formula SSC-2026.1
Formula SSC-2026.1 · 4,000 PSI
Order volume
11.46 yd³
8.763 m³ placed+waste
Order weight
46,420 lb
21,056 kg
80 lb bags
516
13 pallets at 42 bags
60 lb bags
688
0.45 ft³ yield each
Rebar
696.00 ft
47 × 20 ft · 49 × 6 m · 511 lb
Ready-mix vs bags
$1,891.19
Truck $1,891.19 · 80 lb bags $3,483.00
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 | 10.42 yd³ | 10% | 11.46 yd³ / 8.763 m³ | USD | $1,891.19 | Source Spec Material / Tool |
| Short-load fee | Full load | — | 2 truck @ 10 yd³ | USD | $0.00 | Source Spec Material / Tool |
| 80 lb pre-mix bags | 468.9 bags | 10% | 516 bags | USD | $3,483.00 | Source Spec Material / Tool |
| 60 lb pre-mix bags | 625.2 bags | 10% | 688 bags | USD | $3,715.20 | Source Spec Material / Tool |
| #4 rebar sticks, 20 ft | 47 sticks | 10% | 52 sticks / 49 × 6 m | USD | $728.00 | Source Spec Material / Tool |
| Rebar chairs | 187 crossings | 10% | 206 chairs | USD | $57.68 | Source Spec Material / Tool |
| Tie wire rolls | 187 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
$1,891.19
1.15 nominal 10 yd³ loads · 2 to order
80 lb bags
$3,483.00
60 lb alternative $3,715.20 · delivery weight 46,420 lb
| Thickness | Order yd³ | Order m³ | 80 lb bags | Rebar ft | Ready-mix | 80 lb cost |
|---|---|---|---|---|---|---|
| 4 in | 7.28 | 5.565 | 328 | 766 | $1,201.04 | $2,214.00 |
| 5 in | 8.32 | 6.365 | 375 | 766 | $1,373.57 | $2,531.25 |
| 6 in | 9.37 | 7.164 | 422 | 766 | $1,546.11 | $2,848.50 |
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 24 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 helps you determine the specifications for a residential concrete slab measuring 16 ft by 24 ft and 8 inches thick, reinforced with #4 rebar spaced at 18 inches. Please note that soil design considerations are excluded from this calculation.
Refer to IRC R506 for guidelines on concrete slab construction, ensuring that your project meets all necessary standards for safety and durability.
Code reference
IRC R506
Field questions
- What is the purpose of using rebar in a concrete slab?
- Rebar provides tensile strength to the concrete, helping to prevent cracking and improve the overall durability of the slab.
- Why is soil design excluded from this calculation?
- Soil design is a complex aspect that requires specific site analysis and is not covered in this general slab calculator.
- What thickness is recommended for a residential slab?
- An 8-inch thickness is commonly recommended for residential slabs, especially when supporting heavier loads.
- How do I ensure compliance with IRC R506?
- Follow the guidelines outlined in IRC R506, which covers the design and construction of concrete slabs, including reinforcement and curing requirements.