Fence Calculator
Planning a fence project starts with an accurate material estimate. This fence calculator takes your total fence length, post spacing, and number of rails per section to instantly compute how many posts, panels, and rails you need — including an adjustment for gate openings that require an extra post on each side.
Whether you're installing a wood privacy fence, a split-rail fence, or a chain-link enclosure, knowing your post count and rail count up front prevents over-ordering or costly mid-project supply runs. Simply enter your measurements in feet or meters, choose your post spacing (8 ft / 2.4 m is the most common), and set the number of horizontal rails per section.
How it works
Sections = ⌈Total Length ÷ Post Spacing⌉ (ceiling). Posts = Sections + 1 + Gate Count (each gate adds one extra post for the closing side). Rails = Sections × Rails per Section.
Use cases
- Estimating lumber and hardware for a backyard wood fence
- Calculating post count for a split-rail or horse fence
- Planning materials for a vinyl or PVC panel fence installation
- Budgeting a chain-link fence around a residential or commercial property
- Determining rail and post quantities before ordering at a home-improvement store
Frequently asked questions
How many fence posts do I need for 100 feet of fence?
With the common 8 ft post spacing, 100 feet works out to 13 sections (100 ÷ 8 rounded up) and therefore 14 posts, since posts always equal sections plus one. Add one more post for every gate opening in the run.
What is the standard spacing between fence posts?
The most common post spacing is 8 feet (about 2.4 meters), which matches standard panel and rail lengths. Heavier panels, windy sites, or taller fences often call for tighter spacing, such as 6 feet, for extra rigidity.
How do gates change the number of posts I need?
Each gate opening requires one extra post so the gate has a dedicated post on both the hinge side and the closing side. The calculator handles this automatically: posts = sections + 1 + number of gates.
How do I calculate how many fence rails I need?
Multiply the number of sections by the rails per section: rails = sections × rails per section. Most privacy fences use 2 to 3 horizontal rails per section, while split-rail fences typically use 2 or 3 depending on the style.
Why does the calculator round the number of sections up?
If your total length is not an exact multiple of the post spacing, you still need a full extra section to close the remaining gap. Rounding up (the ceiling function) ensures the final short section is counted, so you never come up short on posts or rails.