How Many Bags of Concrete for a 8x12 Shed Base?
A 8x12 slab at 4" needs 59 bags of 80 lb concrete.
59bags
80 lb bags · estimated $411.82 at $6.98/bag
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Estimated cost: ~$411.82 (59 × $6.98/bag, Spring 2026 pricing)
Quick presets
Bag size
Material list
- 59 × 80 lb concrete mix bags — $411.82 @ $6.98/bag (Spring 2026)Home Depot ↗Lowe's ↗
- Wheelbarrow or mixing tub
- Mixing hoe or drill paddle
- Margin trowel or float
Multi-bag comparison
| Bag size | Bags | Price/bag | Total |
|---|---|---|---|
| 80 lbBest value | 59 | $6.98 | $411.82 |
| 60 lb | 79 | $5.98 | $472.42 |
| 40 lb | 118 | $4.98 | $587.64 |
Prices are spring 2026 estimates. Above ~60 bags, price a ready-mix truck too — it is often cheaper.
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59 bags(80 lb)
$411.82
How this is calculated
We convert your dimensions to cubic feet, add a 10% waste buffer for spillage and an uneven subgrade, then divide by the bag's yield and round up to the next full bag.
FAQ
How many bags of concrete for a 8x12 shed base?
A 8x12 shed base at 4 inches needs about 59 bags of 80 lb or 79 bags of 60 lb concrete, including a 10% waste allowance.
How much does a 8x12 concrete shed base cost?
About $412 in 80 lb bags at current prices.
How many cubic feet of concrete is a 8x12 slab at 4 inches?
About 32 cubic feet, or 35.2 cubic feet once the 10% waste buffer is added.
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