Concrete Bag Calculator
For small jobs like a pad for an AC unit, a few stepping stones or a shed base, bagged mix is the way to go. Enter the size and thickness to see the number of bags in each common size.
Bag counts are rounded up to whole bags and include the extra you set for waste. For fence and mailbox posts, use the post calculation on the fence calculator instead, since post holes are round.
How it’s calculated
- Cubic feet = length × width × thickness (in) ÷ 12.
- Bags = cubic feet × (1 + waste %) ÷ bag yield, rounded up.
- Yields: 80 lb ≈ 0.60 cu ft, 60 lb ≈ 0.45 cu ft, 40 lb ≈ 0.30 cu ft.
Concrete for common slab sizes
- 3×3
- 3×4
- 3×5
- 3×6
- 3×8
- 3×10
- 3×12
- 3×14
- 3×15
- 3×16
- 3×18
- 3×20
- 3×22
- 3×24
- 3×25
- 3×26
- 3×28
- 3×30
- 3×32
- 3×36
- 3×40
- 3×50
- 4×4
- 4×5
- 4×6
- 4×8
- 4×10
- 4×12
- 4×14
- 4×15
- 4×16
- 4×18
- 4×20
- 4×22
- 4×24
- 4×25
- 4×26
- 4×28
- 4×30
- 4×32
- 4×36
- 4×40
- 4×50
- 5×5
- 5×6
- 5×8
- 5×10
- 5×12
- 5×14
- 5×15
- 5×16
- 5×18
- 5×20
- 5×22
- 5×24
- 5×25
- 5×26
- 5×28
- 5×30
- 5×32
- 5×36
- 5×40
- 5×50
- 6×6
- 6×8
- 6×10
- 6×12
- 6×14
- 6×15
- 6×16
- 6×18
- 6×20
- 6×22
- 6×24
- 6×25
- 6×26
- 6×28
- 6×30
- 6×32
- 6×36
- 6×40
- 6×50
- 8×8
- 8×10
- 8×12
- 8×14
- 8×15
- 8×16
- 8×18
- 8×20
- 8×22
- 8×24
- 8×25
- 8×26
- 8×28
- 8×30
- 8×32
- 8×36
- 8×40
- 8×50
- 10×10
- 10×12
- 10×14
- 10×15
- 10×16
- 10×18
- 10×20
- 10×22
- 10×24
- 10×25
- 10×26
- 10×28
- 10×30
- 10×32
- 10×36
- 10×40
- 10×50
- 12×12
- 12×14
- 12×15
- 12×16
- 12×18
- 12×20
- 12×22
- 12×24
- 12×25
- 12×26
- 12×28
- 12×30
- 12×32
- 12×36
- 12×40
- 12×50
- 14×14
- 14×15
- 14×16
- 14×18
- 14×20
- 14×22
- 14×24
- 14×25
- 14×26
- 14×28
- 14×30
- 14×32
- 14×36
- 14×40
- 14×50
- 15×15
- 15×16
- 15×18
- 15×20
- 15×22
- 15×24
- 15×25
- 15×26
- 15×28
- 15×30
- 15×32
- 15×36
- 15×40
- 15×50
- 16×16
- 16×18
- 16×20
- 16×22
- 16×24
- 16×25
- 16×26
- 16×28
- 16×30
- 16×32
- 16×36
- 16×40
- 16×50
- 18×18
- 18×20
- 18×22
- 18×24
- 18×25
- 18×26
- 18×28
- 18×30
- 18×32
- 18×36
- 18×40
- 18×50
- 20×20
- 20×22
- 20×24
- 20×25
- 20×26
- 20×28
- 20×30
- 20×32
- 20×36
- 20×40
- 20×50
- 22×22
- 22×24
- 22×25
- 22×26
- 22×28
- 22×30
- 22×32
- 22×36
- 22×40
- 22×50
- 24×24
- 24×25
- 24×26
- 24×28
- 24×30
- 24×32
- 24×36
- 24×40
- 24×50
- 25×25
- 25×26
- 25×28
- 25×30
- 25×32
- 25×36
- 25×40
- 25×50
- 26×26
- 26×28
- 26×30
- 26×32
- 26×36
- 26×40
- 26×50
- 28×28
- 28×30
- 28×32
- 28×36
- 28×40
- 28×50
- 30×30
- 30×32
- 30×36
- 30×40
- 30×50
- 32×32
- 32×36
- 32×40
- 32×50
- 36×36
- 36×40
- 36×50
- 40×40
- 40×50
- 50×50
Questions
- How many square feet does an 80 lb bag of concrete cover?
- At 4 inches thick, an 80 lb bag covers about 1.8 square feet. At 2 inches it covers about 3.6 square feet.
- How many 80 lb bags make a yard?
- 45 bags of 80 lb mix make one cubic yard.
- Should I buy 60 or 80 lb bags?
- 80 lb bags cost less per cubic foot, but 60 lb bags are easier to lift and pour. The total cost difference on a small job is usually a few dollars.