Fence calculator: posts, rails, pickets and cost
This fence calculator turns a fence length into a shopping list. Enter the run, the height, how far apart the posts go and how many gates you want, choose a style — boards on rails, pre-made panels, post and rail, or chain link — and it returns the posts (with the length to buy, including the part in the ground), rails, pickets or panels, screws, concrete bags and gates, with a cost estimate from the prices you add.
The arithmetic is simple but easy to get wrong on site: the number of posts is one more than the number of sections unless the fence closes on itself, each gate needs its own extra post, pickets are counted from the board width plus the gap you leave, and rails are per section, not per metre. The calculator shows each of these so the quantities can be checked.
Metric and imperial units are supported, waste is added before rounding, and the materials list can be copied or shared.
How to use the Fence Calculator
- Choose metric or imperial and enter the total fence length, the fence height and the post spacing (2.4 m / 8 ft is usual for timber, 3 m / 10 ft for chain link).
- Enter the number of gates and their width. Tick “closed loop” if the fence returns to its start with no free ends.
- Pick the style. For boards and pickets enter the board width and gap (0 for a solid privacy fence) and the rails per section; for chain link enter the roll length.
- Set the concrete bags per post and a waste percentage, and open “Prices” to enter unit prices if you want a cost.
- Read the posts and sections, the full materials table and the total, then copy or share the list for the timber yard.
Fence Calculator features
Four fence styles
Pickets on rails, pre-made panels, post-and-rail and chain-link mesh, each with the right items counted.
Posts done properly
Sections + 1 (or equal for a closed loop) plus one extra per gate, with the post length including a third in the ground.
Pickets from width and gap
Boards are counted as fence run ÷ (board width + gap) so spaced and solid fences both come out right.
Concrete and fixings
Bags of premix per post and screws or nails at two per picket per rail, plus 10%.
Costed materials list
Enter prices per post, rail, picket or panel, gate and bag; the table shows the cost per line and the total.
Copy or share
The whole list as plain text for a message to the supplier.
How the quantities are calculated
- Fence run = total length − (gates × gate width). 48 m with one 1.2 m gate = 46.8 m.
- Sections = run ÷ post spacing, rounded up: 46.8 ÷ 2.4 = 19.5 → 20 sections (the last one is shorter).
- Posts = sections + 1 + gates (sections + gates for a closed loop) = 22. Post length = height + depth, with depth at least a third of the height or 600 mm.
- Rails = sections × rails per section = 60 for three rails. Pickets = run ÷ (picket width + gap) = 46.8 ÷ 0.1 = 468 with 90 mm boards and 10 mm gaps.
- Waste is added to rails, pickets, panels and mesh, then everything is rounded up. Concrete = posts × bags per post.
Typical spacings and sizes
| Fence | Post spacing | Rails | Boards / cover | Post in ground |
|---|---|---|---|---|
| Timber privacy fence, 1.8 m | 2.4 m (8 ft) | 3 | 90–150 mm boards, 0–10 mm gap | 600–750 mm |
| Picket fence, 1.0–1.2 m | 2.4 m | 2 | 70–90 mm pickets, 50–70 mm gap | 450–600 mm |
| Panel fence | panel width (1.83 m / 6 ft, or 2.4 m) | — | one panel per section | 600 mm |
| Post and rail (paddock) | 2.4–3 m | 2–3 | none | 600–900 mm |
| Chain link | 3 m (10 ft) | top rail + tension wire | 15 m / 50 ft rolls | 600–900 mm |
Practical tips
- Buy posts in stock lengths: a 1.8 m fence with 600 mm in the ground needs 2.4 m posts; a 1.2 m picket fence needs 1.8 m posts.
- Gate posts take the hinge load — use a thicker post and two bags of concrete rather than one.
- Sloping ground increases the run slightly and makes panels awkward; boards on rails can follow the slope.
- Concrete for post holes is also covered by the concrete calculator; finish the fence with figures from the paint calculator (use the fence area, both sides). Building a deck next to it? Try the deck board calculator.
Fence Calculator FAQ
How many fence posts do I need for 100 feet?
With posts every 8 ft, 100 ft is 12.5 → 13 sections and 14 posts, plus one more for each gate. The fence calculator rounds the sections up and shows the length of the short last section.
How far apart should fence posts be?
2.4 m (8 ft) for most timber fences, matching standard rail lengths; 1.83 m (6 ft) for 6 ft panels; up to 3 m (10 ft) for chain link. Closer spacing makes a stiffer fence but needs more posts and rails.
How deep should fence posts go?
About a third of the above-ground height and never less than 600 mm (2 ft); 750–900 mm for 1.8 m fences in soft ground or windy sites. The calculator uses this rule to give the post length to buy.
How many pickets per metre of fence?
Divide 1,000 mm by (picket width + gap). For 90 mm pickets with 10 mm gaps that is 10 per metre; for 70 mm pickets with 60 mm gaps, 7.7 per metre.
How many bags of concrete per post?
One 25 kg (50 lb) bag of post-mix for a 100 × 100 mm post in a 600 mm hole; two bags for deeper holes, gate posts or 150 mm posts. Set the figure to match your hole size.
Does the cost include labour?
No — it is a materials estimate from the prices you enter. Add fixings, post caps, gravel for drainage, stain or paint, and labour separately.