Post Hole Concrete Calculator

Hole Depth Guidelines

• 4ft Fence: 18" deep minimum
• 6ft Fence: 24" deep minimum
• 8ft Fence: 30" deep minimum
• Mailbox Post: 24" deep
• Sign Posts: 36" deep for large signs
• Deck Posts: 42" deep (below frost line)

Hole Diameter Guidelines

• Rule of Thumb: 3x post width minimum
• 4x4 Posts: 8-10" diameter holes
• 6x6 Posts: 12-14" diameter holes
• Metal Posts: 6-8" diameter holes

Concrete Types

• Fast-Setting: No mixing, sets in 20-40 minutes
• Regular Mix: General purpose, requires mixing
• High Strength: For heavy loads and gates
• Ready Mix: Pre-mixed, delivered wet

Installation Steps

1. Dig hole to proper depth and diameter
2. Add 4-6" of gravel base for drainage
3. Set post in center of hole
4. Add dry concrete mix around post
5. Add water according to package directions
6. Brace post until concrete sets

Pro Tips

• Check local frost line depth requirements
• Call 811 for utility location before digging
• Slope concrete away from post for drainage
• Use fast-set concrete for fence posts
• Allow 24-48 hours before attaching heavy loads