1,500 lb and 80 lb bags: the calculator's starting point
The concrete weight calculator opens on a 1,500 lb payload and 80 lb bags, which gives 18 bags, 1,440 lb. The 60 lb left is less than one more bag, and the driver has not been counted yet. With 200 lb of people and gear the load is 16 bags, and with 400 lb it is 13.
The calculator's example slab is 10 × 10 ft and 4 inches thick. It needs 56 bags, so it is 4 trips at 18 bags a trip, and the finished slab weighs 5,000 lb at 150 lb per cubic foot.
Bags left after people and cargo
Payload is everything the truck carries: the driver, passengers, tools, a toolbox, a hitch and the bags. Take the rest off first.
| Already aboard | Payload left for bags | 40 lb bags | 60 lb bags | 80 lb bags |
|---|---|---|---|---|
| Nothing else aboard | 1,500 lb | 37 | 25 | 18 |
| 200 lb of people and cargo | 1,300 lb | 32 | 21 | 16 |
| 400 lb of people and cargo | 1,100 lb | 27 | 18 | 13 |
| 600 lb of people and cargo | 900 lb | 22 | 15 | 11 |
Use the payload on the sticker inside the driver's door of your own truck, not a figure for the model or the class. Bag weights are dry weights as sold.
Trips for a slab with 80 lb bags (1,500 lb payload)
Each row is a 4 inch slab with no waste added, at 18 bags a trip.
| Slab | Concrete | 80 lb bags | Trips | Weight of the slab |
|---|---|---|---|---|
| 8 × 8 ft | 21.3 ft³ | 36 | 2 | 3,200 lb |
| 8 × 10 ft | 26.7 ft³ | 45 | 3 | 4,000 lb |
| 10 × 10 ft | 33.3 ft³ | 56 | 4 | 5,000 lb |
| 10 × 12 ft | 40.0 ft³ | 67 | 4 | 6,000 lb |
| 12 × 12 ft | 48.0 ft³ | 80 | 5 | 7,200 lb |
| 12 × 16 ft | 64.0 ft³ | 107 | 6 | 9,600 lb |
Worked example
1,500 ÷ 80 = 18.75, so 18 whole bags. 18 × 80 = 1,440 lb, 60 lb under the payload. 18 × 0.60 = 10.8 cubic feet of concrete.
Bags per load at other payloads
| Payload | 40 lb bags | 60 lb bags | 80 lb bags |
|---|---|---|---|
| 1,000 lb | 25 bags | 16 bags | 12 bags |
| 1,500 lb | 37 bags | 25 bags | 18 bags |
| 2,000 lb | 50 bags | 33 bags | 25 bags |
| 3,000 lb | 75 bags | 50 bags | 37 bags |
Enter your own payload and slab in the concrete weight calculator, or see how many bags of concrete equal a yard and how much concrete weighs.
Want to change anything else? The calculator above is the full Concrete Weight Calculator: edit any number and the results update instantly.
Tools & materials for this project
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Frequently asked questions
How many 80 lb bags of concrete can a truck with a 1,500 lb payload carry?
18 bags, which weigh 1,440 lb, if nothing else is aboard: 1,500 ÷ 80, rounded down. The driver, passengers and other cargo count against the payload, so with 200 lb of people and gear it is 16 bags.
How many trips to haul the concrete for a 10x10 slab?
4 trips with a 1,500 lb payload: the 4 inch slab needs 56 bags of 80 lb mix and one load is 18 bags. For a slab this size it is worth pricing delivery of the bags against the trips.
How much concrete do 18 bags of 80 lb mix make?
About 10.8 cubic feet (0.40 cubic yards), at 0.60 cubic feet a bag. That pours 32.4 square feet of slab 4 inches thick.
Related sizes and guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.