Project ticket
Concrete for deck footings
Initial rectangular example: one 1x1 ft footing at 36in depth with 10% waste needs 6 bags of 80lb premix, 8 bags of 60lb premix, or 0.12 cu yd of concrete. These are alternative supply options. The calculator below starts with this example; adjust it for your actual rectangular footing design.
For rectangular volumes. Use the depth specified for your project; this calculator estimates material quantity, not structural design.
Quantities to confirm
Concrete purchase sheet
The starting yield is an example for this bag size. Replace it with the product label; bag weight alone does not determine yield.
- 80 lb bags3.3 cu ft with allowance ÷ 0.6 cu ft per bag; rounded up.
- 6bags
What this estimate assumes
- Raw volume: 3 cu ft. Waste allowance: 10%.
- Rectangular volume only; the entered depth comes from your design.
- Bag yield entered: 0.6 cu ft/bag. Whole bags provide 0.3 cu ft above the volume with allowance.
- Only the selected supply method is listed; alternatives are not added together.
Name your project & add notes Optional
Includes your quantities, assumptions and space to record the supplier, confirmed quantity, quote and delivery. No account required.
How to check this list before buyingCompare standard bag sizes and volume
Material totals
1 cu yd = 27 cu ft. Bag counts are rounded up to whole bags; volumes are displayed to two decimal places. The two bag sizes are alternatives.
Concrete shopping list
Choose one supply method; do not add these quantities together.
Yield assumptions: one 80lb bag = 0.6 cu ft; one 60lb bag = 0.45 cu ft. Check the actual bag label; products can differ.
The volumes above include the stated waste allowance. Confirm yield, ready-mix ordering increments and delivery requirements with your supplier before purchasing.
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This calculator supports rectangular volumes. The example is 1 x 1 x (36/12) = 3.00 cu ft before waste, or 3.30 cu ft with 10% waste. Bag counts round up to whole bags using the stated yields.
A cylindrical footing needs a calculation based on its circular area. Do not enter a round footing's diameter as both length and width in this rectangular calculator.
The 36in depth is an example input, not a recommended footing depth. Use dimensions from your actual design, with local code, ground conditions, and structural requirements checked by a qualified professional. Confirm bag yield or the final ready-mix quantity with your supplier.