Concrete Bag Calculator
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Results
62 80 lb bags for 1.36 yd³ of concrete
| Bag size | Yield per bag | Bags | Weight |
|---|---|---|---|
| 40 lb | 0.300 ft³ | 123 | 4,920 lb |
| 50 lb | 0.375 ft³ | 98 | 4,900 lb |
| 60 lb | 0.45 ft³ | 82 | 4,920 lb |
| 80 lb | 0.60 ft³ | 62 | 4,960 lb |
How many bags of concrete per cubic yard?
| Bag size | Yield per bag | Bags per cubic yard | Area per bag at 4 in |
|---|---|---|---|
| 40 lb bag | 0.3 ft³ | 90 | 0.9 ft² |
| 50 lb bag | 0.375 ft³ | 72 | 1.13 ft² |
| 60 lb bag | 0.45 ft³ | 60 | 1.35 ft² |
| 80 lb bag | 0.6 ft³ | 45 | 1.8 ft² |
| Bag size | Approx. yield | Bags per m³ |
|---|---|---|
| 20 kg bag | 9.4 L | 107 |
| 25 kg bag | 11.7 L | 86 |
| 30 kg bag | 14 L | 72 |
| 40 kg bag | 18.7 L | 54 |
US yields are the figures printed on standard concrete mix bags. Metric yields are estimated at the same yield per kilogram; check the bag you buy, because high-strength, fast-setting and lightweight mixes can differ.
How to calculate bags of concrete
For example, a 4 × 6 ft pad 4 inches thick is 8 ft³. With 10% waste that is 8.8 ft³, which takes 15 bags of 80 lb concrete or 20 bags of 60 lb concrete.
Bags or ready-mix?
Bags make sense for post holes, small pads, steps and repairs. As a rough guide, once a job needs more than about 45 bags of 80 lb mix (one cubic yard), mixing by hand becomes a long, heavy day, and early batches can begin to set before the last ones are placed. Enter both prices in the calculator to see the exact break-even point at your local prices.
- Weight adds up fast. 45 bags of 80 lb mix weigh 3,600 lb, more than many pickup trucks can safely carry in one trip.
- Rent a mixer for 10+ bags. A small drum mixer produces more consistent concrete than a wheelbarrow and saves your back.
- Buy one or two extra bags. Unused bags store well if kept dry, and many stores accept returns of unopened bags.
Frequently asked questions
How many 80 lb bags of concrete are in a yard?
About 45. A cubic yard is 27 cubic feet and an 80 lb bag yields about 0.60 cubic feet, so 27 ÷ 0.60 = 45 bags. You need 60 bags of 60 lb mix, 72 bags of 50 lb mix or 90 bags of 40 lb mix for the same yard.
How much area does one 80 lb bag of concrete cover?
An 80 lb bag makes about 0.60 cubic feet, which covers roughly 1.8 square feet at 4 inches thick, 2.4 square feet at 3 inches or 1.2 square feet at 6 inches.
Is it better to buy 60 lb or 80 lb bags?
The concrete is the same; only the bag size changes. 80 lb bags mean fewer bags to open and mix, while 60 lb bags are easier to lift and carry. Price per cubic foot is usually similar, so choose what you can handle safely.
How many bags of concrete do I need for a fence post?
For a typical 10-inch-wide, 30-inch-deep hole with a 4×4 post and 4 inches of gravel at the bottom, you need about 1 cubic foot of concrete: two 80 lb bags or three 50 lb bags per post. Use the post hole calculator for your exact hole size.
When should I switch from bags to a ready-mix truck?
Most people switch somewhere around one cubic yard (45 bags of 80 lb mix). Mixing that much by hand is a full day of hard work, and pours that large are hard to finish before the first batches start to set.