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Concrete Calculator

Cubic yards, bags, and total cost for slabs, footings, post holes, steps, and walls.

You'll need
1.36 cu yd · 62 bags
Cost
$195–$270
Project details
What are you pouring?
Slab dimensions
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

How to use this calculator

Pick what you're pouring — slab, footing, post hole, steps, or wall. The right dimension fields appear automatically. Enter the quantity if you're pouring multiples (like 8 fence post holes). The calculator shows volume in both cubic feet and cubic yards, plus the smartest way to buy: bags vs. ready-mix delivery.

Add reinforcement (wire mesh, rebar) and gravel base if your project needs them. Toggle DIY vs. professional pour for labor cost.

Pro tips

Bags vs. ready-mix. Below ~1 cubic yard, bags are cheaper. Above that, ready-mix is faster, more consistent, and usually less expensive per yard. Most ready-mix companies have a 1–3 yard minimum.

Slab thickness matters.Patios and walkways: 4". Driveways: 4–6" (6" if heavy vehicles). Garage floors: 4–6". Always pour over a 4" compacted gravel base for proper drainage.

Reinforce the right way. Slabs over 100 sq ft need wire mesh or rebar to prevent cracking. Footings and walls always need rebar — check your local code for spacing. Fiber mesh added to the mix is a cheap upgrade.

Buy 10% extra.Spillage, uneven subgrade, and over-excavation always eat more than you'd expect. The 10% waste factor is built into your result — don't cut it.

Frequently asked questions

How many 80 lb bags of concrete are in a cubic yard?▾
Each 80 lb bag yields 0.6 cubic feet. A cubic yard is 27 cubic feet, so it takes 45 bags to make one cubic yard. For 60 lb bags it's 60 bags per yard, and for 40 lb bags it's 90 bags per yard.
When does ready-mix make more sense than bags?▾
Anything over 1 cubic yard (about 45 × 80 lb bags) is usually better as ready-mix — faster, more consistent, and typically cheaper per yard. Most ready-mix suppliers have a 1–3 yard minimum charge.
How thick should my concrete slab be?▾
Patios, walkways, and shed floors: 4". Driveways: 4–6". Garage floors: 4–6". Heavy-vehicle areas: 6–8". Always pour over a 4" compacted gravel base.
Do I need rebar or wire mesh?▾
Slabs over 100 sq ft should have wire mesh or rebar to control cracking. Footings, walls, and any structural concrete need rebar — check local building code for spacing (typically 18" grid for slabs, closer for walls). Fiber mesh added to the mix is a budget alternative for non-structural slabs.
How long does concrete take to cure?▾
Walkable in 24–48 hours. Drivable (cars) in 7 days. Full strength in 28 days. Don't pour in extreme heat (over 90°F) or cold (under 40°F) without admixtures.
How much concrete do I need for a 10×10 patio at 4 inches thick?▾
10 × 10 × (4/12) = 33.3 cubic feet, or 1.23 cubic yards. With 10% waste that's about 1.4 cubic yards (ready-mix) or 60 × 80 lb bags (about 4,800 lbs of dry mix).
Disclaimer. This calculator provides estimates for planning purposes. Actual material quantities and costs may vary based on site conditions, material availability, and local pricing. Always consult a licensed contractor for precise project quotes.