Free Concrete Bag Calculator
Calculate How Many Bags of Concrete You Need
Slab: 4″, Post: 12″
📋 How to Calculate Concrete Bags
- Volume (cu ft) = Length × Width × (Depth ÷ 12)
- Bags = Volume ÷ Bag Yield
Bag Yields: 40lb=0.30 | 60lb=0.45 | 80lb=0.60 cu ft
❓ Concrete Bag FAQ
How many bags of concrete do I need?
Volume (cu ft) ÷ Bag Yield. 80lb bag = 0.60 cu ft. Always round up and add 10% for waste.
How many 80lb bags per cubic yard?
Approximately 45 bags per cubic yard. 27 ÷ 0.60 = 45 bags.
How much concrete for a 10×10 slab?
10’×10’×4″ = 33.3 cu ft = 1.23 cu yd ≈ 56 bags of 80lb concrete.
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