Concrete Bag Calculator — How Many Bags Do You Need?
Who this is for: For anyone staring at a volume number and a store shelf — post holes, AC pads, mailbox bases, and small pours where you buy by the bag and want the count before driving to the yard.
Not the right tool for: Ready-mix orders — trucks price by the yard; bags only make sense for small pours
Work backwards: enter the volume you need in cubic yards or feet and get exactly how many 80, 60, or 40-lb bags to buy — pallet math included.
Quick answer: 45 eighty-pound bags (or 60 sixty-pound bags) make one cubic yard before waste — about 50/66 with a 10% waste factor. Bags make sense under roughly ½ yard; over 1 yard, ready-mix usually wins on price and time.
Use 0.5 for a small pad, 1 for a yard
| 80-lb bag | 0.60 ft³ yield → 45/yd³ |
|---|---|
| 60-lb bag | 0.45 ft³ yield → 60/yd³ |
| 40-lb bag | 0.30 ft³ yield → 90/yd³ |
| Pallet | 42 × 80-lb or 56 × 60-lb bags |
How many bags of concrete do I need?
Bag math runs on published yields: an 80-lb bag produces about 0.60 ft³ of mixed concrete, a 60-lb bag about 0.45 ft³, a 40-lb bag about 0.30 ft³. Enter the volume you need — in cubic yards if you have it, cubic feet if you computed it by hand — and the calculator divides by yield and rounds up to whole bags, then groups them into 42-bag (80-lb) or 56-bag (60-lb) pallets so you know whether one trip covers it. The crossover to remember: past roughly 1 cubic yard, bag work costs more per yard and takes a crew a full day of mixing where a ready-mix truck finishes in twenty minutes.
Common uses
- Counting bags for post holes and footings before a store run
- Comparing bag cost per yard against ready-mix pricing
- Planning pallet pickups for a small pour day
- Splitting a big job into realistic mixing sessions