How many bags of Quikrete per fence post?
Quick Answer
A standard 4×4 fence post in a 10-inch diameter hole at 24 inches deep needs approximately 1.5 bags of 80-lb Quikrete Fast-Setting Concrete. For a 6×6 post in a 12-inch hole at 36 inches deep, use 3 bags. Quikrete Fast-Setting can be poured dry into the hole — no mixing required.
Quick Reference Table
| Post size / hole | 80-lb Quikrete bags per post |
|---|---|
| 4×4 post / 8" dia / 20" deep | 1 bag |
| 4×4 post / 10" dia / 24" deep | 1.5 bags |
| 4×4 post / 10" dia / 30" deep | 2 bags |
| 6×6 post / 12" dia / 36" deep | 3 bags |
| 6×6 post / 14" dia / 42" deep | 4 bags |
| 4×4 gate post / 12" × 36" | 3 bags |
How to Calculate It Yourself
- 1
Dig hole to proper depth: one-third to one-half the post height above ground. For a 6-ft fence, dig 24–30 inches deep.
- 2
Add 3–4 inches of gravel at the bottom for drainage.
- 3
Set post, check plumb in both directions.
- 4
Pour dry Quikrete Fast-Setting mix around post. Add water per bag label (about 1 gallon per bag). Done — no mixing needed. Sets in 20–40 minutes.
Pro Tip
Gate posts take the most stress — always use 3+ bags and consider a 12-inch diameter hole. A sagging gate is almost always caused by an undersized or shallow post footing.
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