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Concrete Cubic Yard Calculator

Ready-mix is ordered by the cubic yard. Enter your pour to get the yardage to tell the supplier, with extra for waste.

What are you pouring?
Units

Slab, patio or driveway

4 in is typical for patios and walks; 5–6 in for driveways and garage floors.

Bag size
Add your prices (optional)

Use your supplier's prices. We don't show average prices because they vary too much by area.

Concrete needed

5.43 cubic yards

146.7 ft³ · 4.15 m³ · includes 10% extra

You need about 5.43 cubic yards of concrete, or 245 bags of 80 lb mix.

Bags of premix

  • 48940 lb bags
  • 39250 lb bags
  • 32660 lb bags
  • 24580 lb bags
  • Before extra4.94 yd³ (133.3 ft³)
  • Weight of bags19,600 lb
  • Ready-mix costAdd a price per yd³
  • Bagged costAdd a price per bag

One 80 lb bag makes about 0.60 ft³ (manufacturer's published yield). Bags are rounded up.

At 5.43 yd³, bags are not realistic (245 × 80 lb). This is a ready-mix pour, often with a contractor's crew and sometimes a pump.

Estimate only, not a quote or engineering advice. Disclaimer

How to calculate cubic yards of concrete

  1. Measure length, width and depth, and convert all three to feet (inches ÷ 12).
  2. Multiply them to get cubic feet.
  3. Divide by 27, because a cubic yard is 3 ft × 3 ft × 3 ft = 27 ft³.
Cubic yards = (L × W × D in feet) ÷ 27 · Cubic meters = cubic yards × 0.7646
Volume conversions
Sizeft³yd³m³
1 ft × 1 ft × 1 ft1.000.0370.028
1 yd × 1 yd × 1 yd27.001.0000.765
81 sq ft at 4 in27.001.0000.765
100 sq ft at 4 in33.331.2350.944
100 sq ft at 6 in50.001.8521.416

Ordering ready-mix

Give the supplier the yardage with your waste allowance included, rounded up to the increment they sell. Tell them what you are pouring and how the truck will reach it. Many suppliers have a minimum order and charge extra for small ("short") loads, and they bill for time the truck waits on site, so have forms, tools and helpers ready. More in ready-mix vs bags.

Already know the yardage? Choose Volume in the calculator to turn yards into bags, or see bags in a yard.

Frequently asked questions

How do I calculate yards of concrete?

Multiply length × width × depth in feet and divide by 27. For a slab with the thickness in inches: length × width × inches ÷ 12 ÷ 27.

How many cubic yards for a 20x20 slab?

A 20 × 20 ft slab is 4.94 yd³ at 4 inches and 7.41 yd³ at 6 inches, before waste. With 10% extra: 5.43 and 8.15 yd³.

How many cubic feet are in a yard of concrete?

27. A cubic yard is a cube 3 feet on each side, and 3 × 3 × 3 = 27.

How much does a cubic yard of concrete weigh?

Roughly 3,800 lb (about 1.9 tons) using the 140 lb/ft³ unit weight QUIKRETE lists for its Concrete Mix. Ready-mix designs vary a little either way.

Related

Sources