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Concrete Slab Calculator

Calculate concrete for any slab: patio, walkway, garage floor, shed pad, or workshop. Get cubic yards, bag count, weight, and total cost — bags vs. ready-mix comparison built in.

You'll need
1.36 cu yd · 62 bags
Cost
$195$270
Project details
What are you pouring?
Slab dimensions
Length (L)Width (W)T
Quantity

e.g. 8 fence post holes, 3 footings

How you'll buy it
💡 Ready-mix recommended
Your project is ≥1 cubic yard — ready-mix delivery is faster, more consistent, and usually cheaper than 62 bags.

Leave blank to use estimate

Default estimate: $130–$180/yd. Most suppliers have a 1–3 yard minimum.

Reinforcement & site prep
Labor

Cost breakdown

Showing ready-mix pricing (recommended for your volume).
Ready-mix concrete · 1.50 cu yd$195 – $270
Total project cost$195 – $270
💡 Comparison: 62 80-lb bags would cost $372$620; ready-mix (1.50 yd) would cost $195$270.

Shopping list

Everything you need for this pour.
  • Ready-mix concrete (delivered)1.50 cu yd
  • 2×4 lumber for forms40 lf
  • Concrete mixing tub or wheelbarrow1
  • Mason hoe or mixing tool1
  • Bull float, edger, groover1 set
  • Gloves, eye protection, knee pads1 set
Ready to pour?
Get quotes from ready-mix suppliers in your area.
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Math breakdown

Step-by-step from your inputs.
Slab volume · 10 × 10 × (4"/12)33.33 cu ft each
With 10% waste factor36.67 cu ft
Cubic yards · cu ft ÷ 271.36 cu yd
Estimated weight (wet)5,317 lbs
80 lb bags · ÷ 0.6 cu ft per bag62 bags

Pro tips

4 inches for foot traffic, 6 inches for vehicles. Patios and walkways: 4 inches. Garage floors and driveways: 4-6 inches. Heavy-duty industrial slabs: 6-8 inches. Pour over a 4-inch compacted gravel base.

Reinforce slabs over 100 sq ft. Plain concrete cracks. Wire mesh ($0.30-$0.50/sq ft) prevents most cracking on slabs over 100 sq ft. Fiber-reinforced mix is another low-cost upgrade.

Cut control joints. Every 8-10 feet, cut a control joint 1/4 the slab thickness deep. Cracks happen anyway — control joints make them happen in straight lines you chose, not random.

Frequently asked questions

How much concrete for a 10×10 slab at 4 inches?
10 × 10 × (4/12) = 33.3 cubic feet, or 1.23 cubic yards. With 10% waste: about 1.4 cubic yards (ready-mix) or 60 × 80 lb bags.
Bags or ready-mix for slabs?
Anything under 1 cubic yard: bags are easier. Above that: ready-mix is faster, more consistent, and often cheaper per yard. Most ready-mix suppliers have a 1-3 yard minimum.
Do I need rebar in a slab?
For non-structural slabs (patio, shed pad), wire mesh is enough. For structural slabs supporting columns or heavy loads, use rebar at 18-inch grid spacing. Always check local code.
How long does a concrete slab take to cure?
Walkable in 24-48 hours. Drivable (cars) in 7 days. Full design strength at 28 days. Keep newly-poured slabs damp for 3-7 days for maximum strength.

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Disclaimer. This calculator provides estimates for planning purposes. Actual material quantities and costs may vary based on site conditions, material availability, and local pricing.