Fence details
Type feet and inches like 12'6" or just 12.5. Add a run for each straight line of fence, or pick Closed yard to fence all four sides. Everything is saved on this device.
About the fence calculator
This free fence calculator tells you how many posts, rails, pickets or panels and bags of concrete you need for a fence. Enter the length of each straight run, or pick Closed yard to fence all four sides of a rectangle. Add your gates, and you get a shopping list you can copy.
The calculator counts each kind of post on its own: line posts, corner posts, end posts and gate posts. That matters, because corner and gate posts are often bigger and cost more.
Features
- Runs and closed yards — add as many straight runs as you like, or fence a whole rectangle at once
- Post spacing — 6 ft or 8 ft, or your own distance (1.8 m and 2.4 m in metric)
- Pickets or panels — boards on rails, or ready-made panels
- Gates — set the number and width; the gap is taken off the fence and gate posts are added
- Four kinds of post — line, corner, end and gate, plus the post length you need
- Concrete — bags for all the posts, worked out from the hole size and how deep the post goes
- Waste and gaps — extra boards for cuts and a gap between boards
- Copy the list — take the shopping list to the shop
How to use it
- Choose Feet & inches or Metres & cm
- Enter the length of the first run. Use Add another run for each more straight line, and fill in Corners on this run if the fence turns
- Or pick Closed yard and type the length and width
- Choose boards on rails or ready-made panels, and the post spacing
- Enter the fence height, then the number of gates and their width
- Read the posts, boards, rails, concrete and screws, then press Copy the list
How the posts are counted
Each side is cut into sections no longer than the post spacing, and the number of sections is rounded up. A straight run with 13 sections needs 14 posts. A closed yard needs one post for each section, and four of them are corner posts. Each gate takes off its width and adds two gate posts. These posts are for a straight fence:
| Spacing | 50 ft | 100 ft | 150 ft | 200 ft |
|---|---|---|---|---|
| 6 ft | 10 posts | 18 posts | 26 posts | 35 posts |
| 8 ft | 8 posts | 14 posts | 20 posts | 26 posts |
Wider spacing saves posts and concrete, but the rails sag more. For a tall privacy fence, 6 ft spacing is stronger.
Worked examples
These numbers come from the calculator itself:
| Fence | Posts | Boards or panels |
|---|---|---|
| 100 ft run, 8 ft spacing, 6 ft high, boards, 2 rails | 14 (12 line + 2 end) | 220 boards, 26 rails |
| 50 ft run with 1 corner + 30 ft run, 8 ft spacing, 3 rails | 13 (8 line + 4 end + 1 corner) | 177 boards, 33 rails |
| Closed yard 40 × 30 ft, 6 ft spacing, 1 gate of 4 ft | 24 (18 line + 4 corner + 2 gate) | 23 panels |
The 100 ft fence uses 1 × 6 boards (5½ in wide) with a ¼ in gap and 5% extra. That is 209 boards, and 220 with the extra. It also needs 35 bags of 50 lb concrete, which is about 2½ bags a post. The closed yard needs 59 bags.
How much concrete for fence posts?
The calculator buries each post one third of the fence height, but never less than 2 ft. A 6 ft fence has 2 ft in the ground, so the post must be at least 8 ft long. The hole is 10 in wide, and the 4 × 4 post takes up some of it. That leaves about 0.92 cubic feet of concrete a post. One 50 lb bag makes about 0.375 cubic feet, so plan on 2½ bags a post. Change the hole width or bag size under More options.
Frequently asked questions
How many fence posts do I need?
Divide the length by the post spacing, round up, and add one post for a straight run. 100 ft at 8 ft spacing is 13 sections, so 14 posts. Gates and corners change the count, and the calculator does that for you.
How far apart should fence posts be?
Most wood fences use 6 to 8 ft. Panels set the spacing: a 6 ft panel needs posts 6 ft apart. Check your local rules for height and distance from the property line.
How many pickets do I need per foot?
Divide 12 inches by the board width plus the gap. A 5½ in board with no gap gives about 2.2 boards per foot. 100 ft needs about 218 boards before waste.
How many rails does a fence need?
Use 2 rails for fences up to about 4 ft, and 3 rails for a 6 ft fence so the boards stay straight.
Does the calculator include the gate?
It takes the gate opening off the fence and adds two gate posts. The gate itself and its hinges and latch are not counted.
Are the screw numbers exact?
No. They are a rough guide: two fasteners where each board crosses a rail, rounded up. Buy a box more.
Good to know
- Call before you dig. Underground pipes and cables are a real risk.
- Measure along the ground, and for a slope, measure along the slope.
- The numbers are estimates. Buy a few extra boards and one extra bag.
- Post length, rails and fasteners depend on your design; check the plan with your supplier.
- Everything stays on your device.
Related tools
- Concrete Calculator — bags of concrete for slabs and holes
- Gravel Calculator — gravel for post holes and paths
- Mulch, Soil & Gravel Calculator — beds along the fence
- Square Footage Calculator — measure your yard
- Unit Converter — feet, inches and metres
