Ready-mix concrete bags calculator for DIY projects. Calculate how many 40lb, 60lb, or 80lb concrete bags you need.

Calculator Settings

Feet & Inches
Meters
Select your preferred measurement unit for your project.
40 lb Bag
0.30 ft³ per bag
60 lb Bag
0.45 ft³ per bag
80 lb Bag
0.60 ft³ per bag
Select the size of ready-mix concrete bags you plan to use.
Slab / Patio
Footing
Post Hole
Wall
Steps
Custom
Select the type of project you're working on.

Slab Dimensions

feet
feet
inches
Nos.
$
$
$
Enter current prices for cost estimation. Leave as is for average market prices.
Bag Yield Information:
• 40 lb bag: Yields approximately 0.30 cubic feet
• 60 lb bag: Yields approximately 0.45 cubic feet
• 80 lb bag: Yields approximately 0.60 cubic feet
• Always buy 10% extra to account for spillage and uneven surfaces
Tips for Using Ready-Mix Concrete:
• Mix only what you can use in 30-45 minutes
• Add water gradually - don't make it too wet
• For large projects, consider ordering ready-mix concrete by the truck
• Always wear protective gloves and eyewear
• Store unused bags in a dry place

CONCRETE BAGS CALCULATION

Concrete Bags Required
45
40 lb bags
Including 10% wastage allowance
Volume Calculation
Total Volume13.33 ft³
Bag Yield0.30 ft³/bag
Without Wastage41 bags
For 1 slab of 10ft × 8ft × 4in
Compare Bag Sizes
40 lb
40 lb Bags
0.30 ft³ per bag
45 bags
60 lb
60 lb Bags
0.45 ft³ per bag
30 bags
80 lb
80 lb Bags
0.60 ft³ per bag
23 bags
Project Details
Project TypeSlab / Patio
Selected Bag40 lb bags
UnitsFeet & Inches
Quantity1 Nos.
Total Bags Needed45 bags
Calculation Details:
• Volume = Length × Width × Thickness
• = 10ft × 8ft × (4in ÷ 12)
• = 10 × 8 × 0.333 = 26.67 ft³ (for 4" thickness)
• Correction: Actually 4" = 0.333ft, so 10×8×0.333 = 26.67 ft³
• For 40 lb bags (0.30 ft³ per bag): 26.67 ÷ 0.30 = 88.9 bags
• With 10% wastage: 88.9 × 1.10 = 97.8 ≈ 98 bags
Cost Estimation
$ 202.50
Based on $4.50 per 40 lb bag
Note: Prices vary by location and brand. Always check local prices.
Results will include all calculation details and shopping list
Shopping Tip: For projects requiring more than 50 bags, consider ordering ready-mix concrete delivered by truck. It's often more economical and less labor-intensive than mixing many bags.