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.
Assumptions to Check
Before ordering materials, confirm the dimensions, product coverage, waste factor, and local installation requirements for your project. Manufacturer coverage tables and local code rules can change the final quantity, especially for structural work, exterior projects, and irregular layouts.
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