How Many Bags of Concrete Do I Need?
Use your project dimensions to estimate the cubic yards of concrete you need, then compare that volume with the yield printed on the bag you plan to buy.
Use a concrete calculator first
For a rectangular slab, enter the length, width, and thickness in the ATHENA Concrete Calculator. The calculator converts your dimensions to cubic yards and adds a 10% planning allowance to the recommended order quantity.
How many 80-lb bags are in a cubic yard?
ATHENA uses about 45 80-lb bags per cubic yard as a planning estimate. Actual yield varies by product, so use the manufacturer's coverage or yield when available.
How many 60-lb bags are in a cubic yard?
ATHENA uses about 60 60-lb bags per cubic yard as a planning estimate. Check the product label because bag yield can vary between concrete mixes.
How do I calculate bags from the package yield?
When the manufacturer gives a cubic-foot yield per bag, convert the project volume to cubic feet first. There are 27 cubic feet in one cubic yard.
Bags = recommended cubic yards × 27 ÷ cubic feet per bag
Round the result up to a whole bag. When the package states coverage for a particular slab thickness instead, use the stated coverage for that product.
Example: a 30 × 10 ft slab at 4 inches
A 30 × 10 ft area at 4 inches is about 3.7 cubic yards before the planning allowance. With the 10% allowance used by ATHENA, the planning quantity is about 4.1 cubic yards.
At ATHENA's planning yields, that is roughly 185 80-lb bags or 247 60-lb bags. These are planning estimates, not a substitute for the yield printed on the product you will purchase.
Bagged concrete vs. ready-mix
Bagged mix requires individual handling and mixing, while ready-mix is delivered by truck and commonly quoted in cubic yards. For a larger pour, compare your calculated volume with the supplier's minimum order, delivery requirements, and recommended quantity.
What should I check before buying?
Confirm the bag weight, stated yield or coverage, mix type, number of bags per pallet if relevant, and the exact project volume. Different products can produce different quantities even when the bag weights are similar.
Ready to plan the order?
Run the full calculation here: Concrete Calculator. You can also read Concrete Bag Calculator for the conversion method or Concrete Calculator for a Slab for a slab-specific example.
Compare 80-lb concrete mix on Amazon (paid link)
Important planning note
For ready-mix deliveries, confirm the final cubic-yard order with your concrete supplier. For bagged mixes, confirm coverage and yield on the exact product package before buying.
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