10 by 24 ft slab at 8 inches
Calculate the specifications for a residential slab measuring 10 ft by 24 ft 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
7.39 yd³
5.648 m³ placed+waste
Order weight
29,920 lb
13,571 kg
80 lb bags
333
8 pallets at 42 bags
60 lb bags
444
0.45 ft³ yield each
Rebar
474.00 ft
39 × 20 ft · 39 × 6 m · 348 lb
Ready-mix vs bags
$1,218.96
Truck $1,218.96 · 80 lb bags $2,247.75
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 | 6.72 yd³ | 10% | 7.39 yd³ / 5.648 m³ | USD | $1,218.96 | 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 | 302.2 bags | 10% | 333 bags | USD | $2,247.75 | Source Spec Material / Tool |
| 60 lb pre-mix bags | 403.0 bags | 10% | 444 bags | USD | $2,397.60 | Source Spec Material / Tool |
| #4 rebar sticks, 20 ft | 39 sticks | 10% | 43 sticks / 39 × 6 m | USD | $602.00 | Source Spec Material / Tool |
| Rebar chairs | 119 crossings | 10% | 131 chairs | USD | $36.68 | Source Spec Material / Tool |
| Tie wire rolls | 119 ties | 10% | 1 rolls | USD | $8.00 | Source Spec Material / Tool |
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Ready-mix truck
$1,218.96
0.74 nominal 10 yd³ loads · 1 to order
80 lb bags
$2,247.75
60 lb alternative $2,397.60 · delivery weight 29,920 lb
| Thickness | Order yd³ | Order m³ | 80 lb bags | Rebar ft | Ready-mix | 80 lb cost |
|---|---|---|---|---|---|---|
| 4 in | 5.00 | 3.821 | 225 | 521 | $824.59 | $1,518.75 |
| 5 in | 5.60 | 4.278 | 252 | 521 | $923.19 | $1,701.00 |
| 6 in | 6.19 | 4.735 | 279 | 521 | $1,021.78 | $1,883.25 |
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 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 assists in determining the requirements for a residential concrete slab measuring 10 ft by 24 ft with a thickness of 8 inches, reinforced with #4 bars spaced at 18 inches on center. Please note that soil design considerations are excluded from this calculation.
Ensure to review the International Residential Code (IRC) R506 for guidelines on concrete slabs, including requirements for reinforcement and curing practices.
Code reference
IRC R506
Field questions
- What is the purpose of using #4 bars in the slab?
- Using #4 bars helps to provide tensile strength to the concrete slab, preventing cracking and ensuring structural integrity.
- Why is soil design excluded from this calculation?
- Soil design is a separate consideration that depends on the specific site conditions, such as soil type and bearing capacity, which are not covered in this calculator.
- What thickness is recommended for a residential slab?
- For most residential applications, a thickness of 4 to 6 inches is common, but in this case, an 8-inch thickness is specified for added strength.