Fence calculator — posts, rails, pickets & concrete
Enter your fence line, spacing and style to get the whole take-off at once: line posts, sections, rails, pickets or boards, and the bags of concrete for the post holes.
Calculator
A 200 ft fence at 8 ft spacing needs about 26 posts, 25 sections, 75 rails and 437 pickets, plus roughly 78 bags of 60 lb concrete for the post holes. Add posts for each gate, end and corner, and order ~10% extra for waste.
A fence take-off is really five small counts stacked together: how many posts hold up the run, how many sections (spans) fall between them, how many rails tie the sections together, how many pickets or boards face the fence, and how much concrete sets the posts. This all-in-one fence calculator runs every count from one measurement — the length of the fence line — plus a handful of labeled planning typicals you can change to match your product.
Measure the line first. Walk the fence run and add up the straight segments in feet, ignoring gate openings for now (you add gate and corner posts separately — see the fence post calculator). The default here is a 200 ft privacy run at 8 ft spacing with 5.5" boards butted tight, three rails per section and 4×4 posts set in 10"×30" holes with 60 lb concrete — a common backyard job that comes out to 26 posts, 25 sections, 75 rails, 437 boards and 78 bags.
Because pickets, panels, spacing and bag yields all vary by product, treat the numbers as a shopping list to confirm, not a spec. Order about 10% extra on pickets and boards for waste, bad ends, corners and terrain, and split the count into materials you buy by the piece (posts, rails, pickets, bags) versus by the run (mesh, top rail — see the chain-link material calculator).
Formula
Each quantity is a closed-form count:
sections = ceil(line_length_ft ÷ post_spacing_ft)\nposts = sections + 1 (add 1 per gate, free end and corner)\nrails = sections × rails_per_section\npickets = ceil(line_length_ft × 12 ÷ (picket_width_in + gap_in))\nhole_vol = π × (hole_dia_ft ÷ 2)² × hole_depth_ft − post_width_ft² × hole_depth_ft\nbags = ceil(hole_vol ÷ bag_yield_cuft) × posts
Bag yields are labeled typicals: a 40 lb bag ≈ 0.30, 50 lb ≈ 0.375, 60 lb ≈ 0.45 and 80 lb ≈ 0.60 cu ft. The +1 on posts is the closing post that every straight run needs; gates, ends and corners each add one more.
Worked example
200 ft run, 8 ft spacing, 5.5" boards butted (0" gap), 3 rails per section, 4×4 posts (3.5"), 10"×30" holes, 60 lb bags:
- sections = ceil(200 ÷ 8) = 25
- posts = 25 + 1 = 26 (before gates/corners)
- rails = 25 × 3 = 75
- pickets = ceil(200 × 12 ÷ 5.5) = ceil(436.4) = 437
- hole = π × (0.417)² × 2.5 − (0.292)² × 2.5 ≈ 1.15 cu ft → ceil(1.15 ÷ 0.45) = 3 bags/post → 3 × 26 = 78 bags
Add a gate and two corners and you would carry three more posts; see the concrete-per-post calculator to compare bag sizes.
From this take-off to a budget
Once you have the counts, price the job with the fence installation cost estimator (material, labor, gates, tear-out and terrain with a contingency) or the simpler cost per linear foot tool. If you are painting or sealing the fence, the fence area & stain calculator turns the same length and height into gallons.
These are planning quantities, not an install spec. Confirm picket width and gap, panel width and concrete bag yield on the actual product, and call 811 to locate buried utilities before you dig a single post hole.
Reference table
Line posts by run length at common spacings (a straight run, before gate/corner posts):
| Line length | 6 ft o.c. | 7 ft o.c. | 8 ft o.c. |
|---|---|---|---|
| 50 ft | 10 | 9 | 8 |
| 100 ft | 18 | 16 | 14 |
| 150 ft | 26 | 23 | 20 |
| 200 ft | 35 | 30 | 26 |
| 300 ft | 51 | 44 | 39 |
Spacing 6–8 ft o.c. is a labeled planning typical; heavier or taller fences use closer posts. Your current spacing: 8.0 ft.