Free Tool

Concrete Bag Calculator

Figure out how many bags of concrete mix you need for small pours — posts, pads, repairs, and DIY projects.

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When to Use Bag Mix vs. Ready-Mix

Bag concrete (Quikrete, Sakrete, etc.) makes sense for small projects: fence posts, mailbox bases, small pads, and repair work. The general rule of thumb:

  • Under 1/2 cubic yard (13.5 cu ft) — bag mix is practical and cost-effective
  • 1/2 to 1 cubic yard — possible with bags but a lot of mixing; consider a small trailer load
  • Over 1 cubic yard — order ready-mix from a concrete plant; bag mixing becomes impractical

Bag Coverage Reference

Bag SizeYield (cu ft)Bags per CYTypical Price
40 lb0.30 cu ft90 bags$3.50 – $5.00
60 lb0.45 cu ft60 bags$4.50 – $6.50
80 lb0.60 cu ft45 bags$5.50 – $8.00

Tips for Bag Concrete

  • Buy 10% extra. Bag yields are approximate, and you'll lose some in mixing and placement.
  • Don't add too much water. The mix should be thick and hold its shape — soupy concrete is weak concrete.
  • Mix time matters. Mix each batch for at least 3-5 minutes for proper hydration.
  • 80 lb bags are heavy. If you're mixing a lot by hand, 60 lb bags save your back. The cost per cubic foot is similar.

From small pours to full foundations

ConstructiveCore handles material estimation, cost tracking, and inventory management for concrete jobs of any size.