60 lb and 80 lb bag count from dimensions
How Many Bags of Concrete Do I Need
Answer first: Enter your project dimensions and bag size. Get the exact bag count with waste, total cost, and a comparison with ready-mix delivery.
10 × 10 ft, 4 in thick
56 bags of 80 lb concrete
With 10% waste. Each 80 lb bag covers about 0.6 ft³.
60 lb bags instead
75 bags for the same slab
Each 60 lb bag covers about 0.45 ft³ — more bags, same concrete.
How Many Bags of Concrete Do I Need?
Enter your dimensions. Get bag count for 60 lb or 80 lb bags with waste included.
80 lb bags needed
62
at 0.6 ft³ per bag
Volume (yd³)
1.36
Bag cost est.
$310
Interactive workflow
Run the numbers, then save or export the project
Bag count formula: the quick answer
Bags = (L × W × T ÷ 12) ÷ bag_yield. Round up — always buy whole bags.
| Benchmark says | Replace with local input | Next check |
|---|---|---|
| No waste added | 10% waste is a standard buffer for formed pours. Use 15% for uneven ground or curves. | The calculator adds waste automatically — adjust the percentage if needed. |
| Wrong bag yield | 80 lb bags yield 0.6 ft³. 60 lb bags yield 0.45 ft³. 40 lb bags yield 0.30 ft³. | Check the bag label — yield can vary by brand and mix. |
| Only bag count, no cost | Multiply bag count × price per bag to get total material cost at the store. | Enter your local bag price in the calculator for a total cost. |
Bag concrete checklist
Before you load the truck for a bag concrete pour.
| Signal to check | What it means | Next step |
|---|---|---|
| Bag size confirmed | You know which bag size you're using (40, 60, or 80 lb). | Check local stock — 80 lb bags are most common but heavier to mix. |
| Waste included | Added 5–15% waste to your bag count. | Use 10% minimum. Better to return an unopened bag than run short. |
| Mixing method | You have a plan for mixing — bucket, mixer, or rented drum mixer. | A rented electric mixer handles 2–3 bags per batch faster than hand mixing. |
| Pour window | You have a 2–4 hour window for mixing and placing. | Bag concrete sets in 20–40 minutes depending on temperature. Plan your batches. |
Related concrete planning tools
Move from a single calculation into a purchase, proposal, or pour-day decision with connected calculators and checklists.
How many bags of concrete do I need for a 10×10 slab?
A 10×10 ft slab at 4 inches thick needs about 56 bags of 80 lb concrete (with 10% waste). For 60 lb bags, that's about 75 bags. Use the calculator above to adjust for your exact dimensions.
How many 80 lb bags of concrete make a cubic yard?
About 45 bags of 80 lb concrete (at 0.6 ft³ each) make one cubic yard (27 ft³). Always add 10% waste, so plan for 50 bags per yard.
How many 60 lb bags of concrete per yard?
About 60 bags of 60 lb concrete (at 0.45 ft³ each) make one cubic yard. With 10% waste, plan for 66 bags per yard.
Is it cheaper to use bags or order ready-mix?
For small pours under 1 cubic yard, bags are often cheaper. Above 1–2 cubic yards, ready-mix delivery usually costs less per yard. Compare both options with the calculator.
How many bags of Quikrete for a post hole?
A standard 12-inch diameter, 3-foot deep post hole needs about 2–3 bags of 80 lb Quikrete. Use the concrete post hole calculator for exact counts based on your hole dimensions.
Planning disclaimer
Bag counts include a waste factor. Actual usage depends on mixing technique, forms, and site conditions. Always check the bag label for the exact yield.