OTHER · FENCE POST
Fence Post Calculator
Calculate how many fence posts, rails, and panels you need for a single run or enclosed yard. Includes post hole depth, concrete bags to buy, and optional cost estimate.
About This Calculator
Enter your fence run length (or yard dimensions for an enclosed rectangle), post spacing, and post size — and instantly see how many posts, panels, and rails to buy, plus recommended hole depth and bags of concrete. Add unit costs for a total material estimate.
How It Works
Posts = floor(totalLength ÷ spacing) + 1 terminal post. Panels = posts − 1. Rails = panels × rails per bay. Hole depth = post length ÷ 3 (bury ≥ 1/3 rule). Concrete = ceil(posts × 1.5 bags/post) — standard 50-lb bag per residential post.
The Formula
posts = floor(length ÷ spacing) + 1 panels = posts − 1
- length
- total fence run length in feet
- spacing
- distance between posts in feet
Frequently Asked Questions
- How deep should fence posts be set?
- The standard rule: bury at least 1/3 of the total post length in the ground, plus add a 6-inch gravel base for drainage. For an 8-ft post (6 ft above ground + 2 ft buried), the hole should be 24–30 inches deep. Frost depth matters in cold climates — in northern US/Canada, posts may need to extend 36–48 inches below grade.
- How many bags of concrete do I need per fence post?
- A standard 10-inch diameter × 24-inch deep hole requires about 1–2 bags of 50-lb concrete mix. This calculator uses 1.5 bags per post as a planning estimate. Always verify with your specific hole dimensions — larger diameter or deeper holes need more concrete.
- What is the difference between this and the fencing calculator?
- The Fencing Calculator estimates linear feet, perimeter, and overall cost per linear foot — useful for material pricing. The Fence Post Calculator focuses on the structural components — post count, rail count, hole depth, and concrete — useful for material orders and labor planning.
- How many rails do I need per fence bay?
- Most residential privacy fences use 2 horizontal rails (top and bottom). Taller fences over 6 ft often use 3 rails for additional support. Farm fences and horse-safe fencing may use 4–5 rails. Set the "Rails per Bay" field to match your design.
Estimates only. Coverage figures (sq ft/gallon, bag yield, BTU/sq ft) are industry rules of thumb with real-world variance. Verify quantities with your supplier before purchasing.