Fence Calculator
Enter your fence length to get post count, picket count, rail count, and concrete bags — gates handled automatically. All inputs saved in the URL.
Enter your fence length to see materials.
What do these results mean?
Posts — the vertical support posts set in concrete. Includes gate posts.
Sections — the spans between posts that receive pickets (gate openings excluded).
Rails — horizontal boards nailed or screwed to the faces of the posts. Pickets attach to these.
Pickets — the vertical boards that form the fence face. Calculated based on total fenced length minus gates, divided by (picket + gap) width.
Concrete bags — 2 bags of 80 lb concrete per post. Adjust for local soil conditions and post depth.
Front Elevation (partial view)
Not to scale
Shopping List
Enter fence length to generate a shopping list.
Check local codes: Many municipalities restrict fence height (commonly 6 ft rear, 4 ft front) and require permits. HOA rules may also apply.
Related Calculators
Methodology
How the fence calculator works.
Posts
Posts = ⌈ length ÷ spacing ⌉ + 1 + (gates × 2). Sections = posts − 1 − gates (gate openings are not picketed sections).
Rails
Rails = sections × rails-per-section. These are the horizontal boards that run between posts and support the pickets.
Pickets
Pickets = ⌈ (length × 12 − gates × 48") ÷ (picketWidth + gap) ⌉. Gate openings (48" each) are subtracted from the total linear footage before dividing.
Concrete
Concrete bags = posts × 2. This assumes standard 80 lb bags and typical hole depth. For posts in soft or wet soil, or posts taller than 6 ft, consider 3 bags per post and consult a local contractor.
FAQ
Frequently asked questions.
How many fence posts do I need?
Posts = ⌈ length ÷ post spacing ⌉ + 1 + gate posts. For example, a 100 ft fence with 8 ft spacing needs ⌈100÷8⌉ + 1 = 14 posts. Each gate adds 2 posts. This calculator handles all of that automatically.
How many bags of concrete per fence post?
This calculator uses 2 bags of 80 lb concrete per post as a typical residential estimate. Actual concrete depends on post diameter, hole depth, and soil conditions. In soft or wet soil you may need 3 bags per post.
How do I calculate fence pickets?
Pickets = ⌈ (total fenced length in inches − gate openings) ÷ (picket width + gap) ⌉. This calculator subtracts gate openings (48" each) and divides by the picket-plus-gap width to get the count.
What is the standard height for a privacy fence?
The most common residential privacy fence height is 6 feet. Many municipalities have height restrictions — typically 6 ft in back yards and 4 ft in front yards. Always check local codes and HOA rules before building.
Should I use 2 or 3 rails per fence section?
Privacy fences 4–5 ft tall typically use 2 rails. Fences 6 ft and taller should use 3 rails for adequate support. Gates almost always need 3 horizontal rails plus diagonal bracing.
Can I save my fence calculation?
Yes — all inputs are saved in the URL. Bookmark the page or share the link to preserve your exact calculation.
Does this work for split-rail fences?
This calculator is optimized for picket and privacy board fences. For split-rail, the post count formula is the same, but rails per section and pickets don't apply. Use the post output and skip the picket count.
How do I account for a gate?
Enter the number of gates in the Gates field. Each gate defaults to a 4 ft opening. The calculator adds gate posts automatically and subtracts gate openings from the picket count.