How Many Bags of Quikrete Do You Need?
Enter your project dimensions below. Instant results for 40lb, 60lb, and 80lb bags — no math required.
Quikrete Bag Calculator
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How to Use This Quikrete Calculator
Enter the length and width of your project in feet, then the thickness in inches. For a standard residential driveway or patio, 4 inches is the typical thickness. For a garage floor or area that will support vehicles, use 5 to 6 inches.
The calculator automatically includes a 10% waste factor by default. This accounts for spillage, uneven subgrade, and the fact that bags don't divide perfectly into your exact volume. You can adjust this percentage up or down depending on your project's complexity.
The results show the number of bags needed for all three common Quikrete bag sizes — 40lb, 60lb, and 80lb — so you can choose based on availability and what you can physically carry.
Pro tip: The 80lb bag is the most economical choice per cubic foot. However, for solo projects or if you have a bad back, the 60lb bag is much more manageable. Always buy a couple extra bags — unused concrete bags store fine if kept dry.
How to Calculate Quikrete Bags by Hand
Understanding the math helps you double-check the calculator and work through irregular shapes. Here's the formula:
- Calculate cubic feet: Length (ft) × Width (ft) × Thickness (ft). Note thickness must be converted from inches — divide by 12. So 4 inches = 0.333 ft.
- Convert to cubic yards: Divide cubic feet by 27. There are 27 cubic feet in one cubic yard.
- Add waste factor: Multiply by 1.10 (for 10% waste).
- Multiply by bags per yard: 45 bags for 80lb, 60 bags for 60lb, 90 bags for 40lb.
Worked Example: 10×12 Patio at 4" Thick
Cubic feet: 10 × 12 × (4/12) = 10 × 12 × 0.333 = 40 cubic feet. Divide by 27: 40 ÷ 27 = 1.48 cubic yards. With 10% waste: 1.48 × 1.10 = 1.63 cubic yards. At 45 bags per yard: 1.63 × 45 = 74 bags of 80lb Quikrete.
Quikrete Coverage Reference Table
| Bag Size | Cubic Feet | Bags per Cu. Yard | Sq Ft at 4" |
|---|---|---|---|
| 40 lb | 0.30 cu ft | 90 bags | ~0.9 sq ft |
| 60 lb | 0.45 cu ft | 60 bags | ~1.35 sq ft |
| 80 lb | 0.60 cu ft | 45 bags | ~1.8 sq ft |
When to Use Bags vs. Ready-Mix Concrete
For projects under roughly 1 cubic yard, Quikrete bags make sense financially. Ready-mix concrete trucks typically have a minimum delivery of 1 yard and charge extra fees for small loads, short loads, and Saturday delivery. Once your project exceeds 1 to 2 yards, the economics shift strongly toward ready-mix, which arrives mixed and ready to pour.
Frequently Asked Questions
- How many 80lb bags of Quikrete do I need for a 10×10 slab at 4 inches?A 10×10 slab at 4 inches thick requires approximately 1.23 cubic yards. At 45 bags per cubic yard, you need about 56 bags. Add 10% for waste and order 62 bags to be safe.
- How much does one 80lb bag of Quikrete cover?One 80lb bag covers 0.60 cubic feet, or about 0.022 cubic yards. At 4 inches thick, that's roughly 1.8 square feet of slab per bag.
- Is Quikrete 5000 or Quikrete 4000 better for a driveway?Quikrete 5000 (5,000 PSI) is the better choice for driveways. It reaches higher strength faster than standard 4,000 PSI mixes and handles vehicle traffic, freeze-thaw cycles, and de-icing chemicals better. The cost difference per bag is small.
- How many bags of Quikrete are in a cubic yard?One cubic yard of concrete requires approximately 45 bags of 80lb Quikrete, 60 bags of 60lb Quikrete, or 90 bags of 40lb Quikrete.
- Can I mix Quikrete by hand without a mixer?Yes, for small jobs under 10 bags, a wheelbarrow and a hoe work fine. For anything larger, rent a cement mixer from your local hardware store. Mixing 80lb bags by hand for 30+ bags is exhausting and you risk inconsistent water ratios which weaken the concrete.