Count the 80 lb bags you need.
⚙️Calculation Parameters
📊Calculated Output
How 80 lb Concrete Bag Calculator Works?
To count 80 lb bags, the 80 lb Concrete Bag Calculator divides the tube volume by 0.60 cubic feet (ft³), the yield of an 80 lb (36 kg) bag. The process takes 4 steps.
Enter the tubes
Type the diameter, depth and count.
Calculate the volume
The calculator finds the fill in ft³, cubic yards (yd³) and liters (L).
Divide by 0.60 ft³
One 80 lb bag yields 0.60 ft³ (17 L). 45 bags make 1 yd³.
Read bags and water
The tool shows the bag count, the total weight and about 3 quarts (2.8 L) of water per bag.
80 lb Concrete Bag Calculator Formula
The 80 lb Concrete Bag Calculator uses a 0.60 ft³ yield.
Bag count
Bags = ⌈V ÷ 0.60⌉V in ft³.
Bags per yard
27 ÷ 0.60 = 45 bags per yd³Useful for bag versus truck checks.
Mixing water
Water ≈ Bags × 0.75 gal (2.8 L)Adjust to the label and the slump you need.
Worked example: 8 piers at 12 in × 48 in, 10% waste
- V = 8 × 3.142 × 1.10 = 27.65 ft³
- Bags = ⌈27.65 ÷ 0.60⌉ = 47 bags
- Water ≈ 47 × 0.75 = 35.2 gal (133 L)
80 lb Concrete Bag Calculator Conversion Table
The 80 lb bag conversion table lists tube height per bag and bags needed at 36 in and 48 in depths.
| Tube | Height per bag | Bags at 36 in | Bags at 48 in | Bags at 48 in + 10% |
|---|---|---|---|---|
| 6 in (15 cm) | 36.7 in | 1 | 2 | 2 |
| 8 in (20 cm) | 20.6 in | 2 | 3 | 3 |
| 10 in (25 cm) | 13.2 in | 3 | 4 | 4 |
| 12 in (30 cm) | 9.2 in | 4 | 6 | 6 |
| 16 in (41 cm) | 5.2 in | 7 | 10 | 11 |
| 18 in (46 cm) | 4.1 in | 9 | 12 | 13 |
One 80 lb bag yields 0.60 ft³ (17 L, 0.017 m³). 45 bags equal 1 yd³.
What is 80 lb Concrete Bag Calculator?
An 80 lb Concrete Bag Calculator is a bag counter set to the 0.60 ft³ yield of an 80 lb (36 kg) bag, the standard contractor size for bagged concrete.
The 80 lb bag gives the lowest cost per cubic foot among common bag sizes and the fewest bags to open and mix. A 12 in tube rises 9.2 in per bag. A 48 in deep 12 in pier takes 6 bags.
The 45-bags-per-yard rule helps decide between bags and a truck. Past about 1 yd³, 45 heavy bags take hours to mix by hand.
What are the uses of 80 lb Concrete Bag Calculator?
There are 4 main uses of the 80 lb Concrete Bag Calculator.
Contractor deck jobs
Builders count 80 lb bags for 4 to 12 deck piers.
Mixer batches
Crews load 2 bags of 80 lb into a 3.5 ft³ drum mixer.
Bag versus truck
Estimators compare the bag count with the 45-bag yard.
Water planning
Crews stage about 0.75 gal of water per bag.
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