What is the purpose of using #4 bars in the slab?

Using #4 bars helps to reinforce the concrete slab, providing additional tensile strength and reducing the risk of cracking.

Why is soil design excluded from this calculation?

Soil design is a complex aspect that depends on various factors such as soil type, load-bearing capacity, and moisture content, which are outside the scope of this calculator.

What are the dimensions of the slab being calculated?

The slab dimensions are 16 feet by 10 feet with a thickness of 6 inches.

How does IRC R506 relate to slab design?

IRC R506 provides guidelines and requirements for the design and construction of concrete slabs, ensuring safety and structural integrity.

16 by 10 ft slab at 6 inches

Calculate the requirements for a residential slab measuring 16 ft by 10 ft at 6 in thick 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

4.24 yd³

3.239 m³ placed+waste

Order weight

17,160 lb

7,784 kg

80 lb bags

191

5 pallets at 42 bags

60 lb bags

255

0.45 ft³ yield each

Rebar

326.00 ft

24 × 20 ft · 24 × 6 m · 240 lb

Ready-mix vs bags

$699.11

Truck $699.11 · 80 lb bags $1,289.25

Slab footprint and rebar gridLive scaled blueprint

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.

Bill of materials and shopping list
Item	Net	Waste	Order	Unit price	Line total	Source Spec Material / Tool
Ready-mix concrete	3.85 yd³	10%	4.24 yd³ / 3.239 m³	USD	$699.11	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	173.3 bags	10%	191 bags	USD	$1,289.25	Source Spec Material / Tool
60 lb pre-mix bags	231.1 bags	10%	255 bags	USD	$1,377.00	Source Spec Material / Tool
#4 rebar sticks, 20 ft	24 sticks	10%	27 sticks / 24 × 6 m	USD	$378.00	Source Spec Material / Tool
Rebar chairs	77 crossings	10%	85 chairs	USD	$23.80	Source Spec Material / Tool
Tie wire rolls	77 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

$699.11

0.42 nominal 10 yd³ loads · 1 to order

80 lb bags

$1,289.25

60 lb alternative $1,377.00 · delivery weight 17,160 lb

Side-by-side thickness comparison at the same footprint
Thickness	Order yd³	Order m³	80 lb bags	Rebar ft	Ready-mix	80 lb cost
4 in	3.48	2.658	157	359	$698.63	$1,059.75
5 in	3.86	2.949	174	359	$761.37	$1,174.50
6 in	4.24	3.239	191	359	$699.11	$1,289.25

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: 16 by 10 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 is designed to assist in the preliminary design of a residential concrete slab measuring 16 ft by 10 ft and 6 inches thick. The slab incorporates #4 rebar spaced at 18 inches on center, which is essential for structural integrity.

Note that soil design considerations are excluded from this calculation, and users should refer to IRC R506 for guidelines on concrete slabs.

Code reference

IRC R506

Field questions

What is the purpose of using #4 bars in the slab?: Using #4 bars helps to reinforce the concrete slab, providing additional tensile strength and reducing the risk of cracking.
Why is soil design excluded from this calculation?: Soil design is a complex aspect that depends on various factors such as soil type, load-bearing capacity, and moisture content, which are outside the scope of this calculator.
What are the dimensions of the slab being calculated?: The slab dimensions are 16 feet by 10 feet with a thickness of 6 inches.
How does IRC R506 relate to slab design?: IRC R506 provides guidelines and requirements for the design and construction of concrete slabs, ensuring safety and structural integrity.