Fence perimeter calculator
Get the total perimeter feet and the post sections that length implies for a rectangular yard, with the spacing math shown.
Fence perimeter
Enter your measurements and the result updates as you type.
Overview
For a rectangular yard, the perimeter is two times the length plus two times the width, and once you have that footage the post-planning math follows from your spacing. This calculator returns both: the perimeter feet and how many post sections a chosen spacing splits the run into.
The section count rounds up, since a partial spacing at the end of the run still needs a section and a post. For a yard that is not a rectangle, walk the boundary with the linear feet calculator instead and feed its total into the full fence take-off.
Common mistakes
- Adding only two sides when the run wraps the yard both directions, which halves the real perimeter.
- Splitting the perimeter by a spacing and rounding down, which leaves the last section short of a post.
- Building the estimate on area instead of perimeter, when posts and rails follow the outline of the lot, not its square footage.
Related calculators
- Fence post calculator Calculate line posts, corner posts and end posts from run length and spacing, with concrete for each post included in the take-off.
- Fence cost calculator Estimate total fence cost from run length, height and your local material and labor rates, with the budget math shown.
- Fence slope calculator Adjust your fence run for a graded yard: slope-adjusted length from the horizontal run, plus a rack-versus-step sanity check.
Related reading
In-depth guides
Frequently asked questions
What is the perimeter of a 150 by 100 foot yard?
The perimeter is 500 feet: two times 150 gives 300, two times 100 gives 200, and the sum is 500. That is the run a fence around the lot would span.
What is the formula for fence perimeter?
Multiply the length by two, multiply the width by two, and add the results together. The perimeter is then divided by your post spacing to plan the sections, rounding up to a whole number.
How many posts for a 500 foot perimeter at 8 foot spacing?
Five hundred feet divided by 8 feet is 62.5 sections, rounded up to 63, which with the end post gives 64 posts for the run before corners and gates are added.
My yard is L-shaped, not a rectangle. What now?
The rectangle formula overcounts on an L-shape unless you subtract the overlap. Instead, measure the actual boundary segment by segment with the linear feet calculator, and use that total as the run through your post spacing.
Does the perimeter change with fence height?
No. Perimeter is ground footage only: height changes board count, panel rows and cost, never the perimeter itself. Use the height and style in the material calculators for the board side of the take-off.
Should gates be subtracted from the perimeter?
Yes. The perimeter tells you the full outline, but panels do not fill gate openings, so subtract gate widths from the run when you order material. Keep the gate posts in the count, since a gate still needs a post on each side.
Is this the same as linear feet?
For a rectangle they coincide: linear feet of fence around the lot equals the perimeter. The two calculators diverge when a lot is irregular, which is when linear feet (measured side by side) is the correct tool.
Can I use this for a pool fence perimeter?
Yes, but restrict it to the barrier footprint rather than the whole yard: the pool fence calculator already carries the height and pool-specific defaults, and pairing the rectangle perimeter with a 4 to 6 foot height scaffold covers the common enclosure layout.