Concrete Bag Calculator
Enter your measurements
Extra to cover cuts, breakage, and mistakes.
Results
- Concrete needed1.36 cubic yards
- Volume36.67 cubic feet
- 60 lb bags82if mixing by bag
- 80 lb bags62if mixing by bag
Estimated cost
per cubic yard of ready-mix, delivered
Material range is per cubic yard of ready-mix delivered for a standard 3,000 to 4,000 PSI mix; for bag mixing, budget about $5 to $7 per 80 lb bag or $4 to $6 per 60 lb bag at retail. Installed range covers ready-mix delivery plus standard flatwork labor (forming, pouring, finishing, and basic curing) for a simple residential slab; decorative finishes, rebar, and vapor barriers add to that.
Estimate only — prices vary by region, supplier, and season. Get a local quote before buying.
This concrete bag calculator tells you exactly how many 60 lb or 80 lb bags you need for a slab, pad, footing, or any rectangular pour, along with the total cubic footage and cubic yardage. Enter your length, width, and thickness, add a waste factor (10 percent is standard for flatwork), and the tool returns bag counts you can take straight to the hardware store. Bagged concrete comes in 40 lb, 60 lb, and 80 lb sizes. An 80 lb bag yields about 0.60 cubic feet of mixed concrete and a 60 lb bag yields roughly 0.45 cubic feet, so heavier bags cost less per cubic foot but are harder to lift repeatedly. That is why a 10 by 10 foot slab at 4 inches thick, one of the most common DIY pours, takes 62 bags at 80 lb or 82 bags at 60 lb. Bag mixing makes sense for small jobs up to about 1 cubic yard; beyond that, ready-mix delivery is almost always faster and cheaper per yard.
How it’s calculated
Volume = Length × Width × Thickness, converted to cubic yards (÷27) and to 60 / 80 lb bag counts.
Worked example
Take a 10 by 10 foot patio slab poured at a standard 4-inch depth with a 10 percent waste allowance. The calculator returns 1.36 cubic yards (36.67 cubic feet) of concrete, which works out to 62 bags of 80 lb mix or 82 bags of 60 lb mix. That bag count gives you a firm shopping list before you rent the mixer.
Inputs
- Length
- 10 ft
- Width
- 10 ft
- Thickness
- 4 in
- Waste / overage
- 10 %
Result
- Concrete needed
- 1.36 cubic yards
- Volume
- 36.67 cubic feet
- 60 lb bags
- 82
- 80 lb bags
- 62
- Estimated material cost
- $190 – $251
Materials & pricing near you
Bagged concrete is stocked at nearly every home center and lumberyard in the US, but prices move with brand, region, and season. At big-box stores, Quikrete and Sakrete 80 lb bags typically run about $5 to $7 and 60 lb bags about $4 to $6; rural and independent suppliers often charge more because of freight. Spring and summer project season tends to firm up pricing, while demand softens in late fall. For larger pours, ready-mix delivered by truck runs roughly $140 to $185 per cubic yard depending on PSI, plant competition, and fuel, and short-load fees on orders under about 5 yards can add $40 to $60 per yard. Most residential flatwork needs no permit, but confirm with your local building department before pouring footings or structural slabs.
Frequently asked questions
How many bags of concrete do I need for a 10x10 slab?
At the standard 4-inch thickness with a 10 percent waste factor, a 10 by 10 foot slab requires about 62 bags of 80 lb mix or 82 bags of 60 lb mix. If you pour at 6 inches instead, common for driveways and heavy loads, those counts jump to roughly 92 and 123 bags respectively, so thickness is the biggest variable to nail down before you shop.
Should I use 60 lb or 80 lb bags?
Eighty-pound bags yield more concrete per trip and cost less per cubic foot, but they are heavy to lift and dump repeatedly. If you are mixing by hand or working alone, 60 lb bags are easier to manage and let you keep a steady pace without a helper. Either size produces the same strength concrete once mixed; the difference is only weight and how many bags you handle.
When does it make more sense to order ready-mix instead of bags?
Most pros draw the line around 1 cubic yard (27 cubic feet). Above that, bagged concrete usually costs more per cubic foot than ready-mix once you add up the bags, and hand-mixing dozens of them becomes a long, exhausting day. A 10 by 10 slab at 4 inches sits right at roughly 1.36 yards, so it is borderline; for a driveway, garage floor, or large footing, call a ready-mix plant.
How do I measure thickness accurately before calculating?
Set your forms first, then measure the actual inside depth with a tape or story pole rather than relying on your planned depth. Subgrade settling, uneven grading, and form flex can all add thickness you did not budget for. Check several points across the pour and use the average, or the deepest reading if you want a safety margin. The 10 percent waste factor in the calculator helps absorb small discrepancies and spillage.