Fence Calculator

1. Enter the total fence length in feet, measured along the planned fence line.
2. Set the fence height in feet (common choices are 4 ft or 6 ft).
3. Choose a fence style: privacy, semi-private, pre-built panel or post-and-rail.
4. Adjust post spacing if needed (standard is 8 ft).
5. For picket-style fences, set the picket width and gap in inches.
6. Enter the number of gates and gate width.
7. Read the full materials list: posts, rails, pickets or panels, post length and concrete bags.

A fence calculator is a material estimator for residential and commercial fencing projects. It takes the total fence length, height, style and spacing and counts every post, rail, picket or panel you need, plus the concrete to set the posts.

Estimating by hand is straightforward for a short run, but a long fence with gates, corners and varying styles can mean hundreds of pieces. The calculator handles the arithmetic so you can focus on layout and design.

The results are a starting-point estimate. Real projects may need extra material for corners, slopes, waste cuts and local code requirements. Always do a site survey before buying materials.

The calculator uses simple division and rounding to count every piece along the fence line.

1. Divide the fence length by the post spacing and round up, then add 1 for the end post.
2. Add 2 extra posts for every gate opening.
3. Multiply sections by the number of rails per section.
4. Convert fence length to inches and divide by the picket width plus gap to get the picket count (or use panel count for panel style).

Why Round Up?

A fence run rarely divides evenly. Rounding up means the last section is shorter than a full bay, which is how real fences are built. You cut the final section to fit rather than leaving a gap.

Take a 100 ft privacy fence, 6 ft high, with 8 ft post spacing, standard 3.5-inch pickets (no gap) and one 4-foot gate.

Posts: ceil(100 / 8) + 1 = 13 + 1 = 14 line posts, plus 2 gate posts = 16 posts.

Rails: (16 - 1) x 2 = 30 rails.

Post length: 6 + 2 = 8 ft each (2 ft buried).

Pickets: ceil(100 x 12 / 3.5) = ceil(342.86) = 343 pickets.

Concrete: 16 x 2 = 32 bags of 50 lb mix.

As a second example, a 50 ft semi-private fence, 4 ft high with 1.5-inch gaps: posts = ceil(50/8)+1 = 8, rails = 14, pickets = ceil(600/5.0) = 120, concrete = 16 bags.

The calculator supports four common fence styles, each affecting how materials are counted.

For board-on-board fences, use the semi-private style with a 5.5-inch picket width and a negative or zero gap. The calculator counts the boards the same way.

Standard post spacing is 8 feet on center. That is the maximum for most wood fences before rails start to sag. In high-wind areas, heavy-panel zones or for chain-link, 6 feet is safer.

Burial Depth

The general rule is to bury one-third of the post length, with a minimum of 2 feet. For a 6-foot fence that means an 8-foot post with 2 feet underground. The calculator uses the 2-foot rule as a default. Frost-line depth may require more in cold climates.

Concrete per Post

Two 50-pound bags of quick-setting concrete (such as Quikrete Fast-Setting) are typical for a standard 4x4 post in a 10-inch-diameter hole. Larger posts (6x6) or deeper holes need more. The calculator labels this as a typical estimate, not a guarantee.

You can run the same math by hand in four steps.

1. Posts: Divide the total fence length by the post spacing. Round up. Add 1 for the end post. Add 2 for every gate.
2. Rails: Multiply the number of sections (posts minus 1) by 2 (or 3 for tall fences).
3. Pickets: Convert the total fence length to inches. Divide by the picket width plus the gap. Round up.
4. Concrete: Multiply the total post count by 2 bags (50 lb each).

Corners, slopes and waste cuts are not included in this basic count. Add 5-10 percent for waste on pickets and rails.

Terrain and Slope

On sloped ground, panels are often stepped, which can increase post count. Picket fences can follow the grade but may need longer pickets at the low end.

Corners and Angles

Every corner or angle needs a post. The calculator assumes a straight run. Add one post for each corner.

Waste and Breakage

Pickets crack, rails split and panels arrive damaged. A 5-10 percent overage on pickets and rails is common practice.

Local Building Codes

Codes may limit fence height, require setbacks from property lines or mandate specific post depths. Check before you buy.

Wind Load

In windy areas, closer post spacing (6 ft instead of 8 ft) and deeper burial give the fence more resistance. Three rails instead of two also help.

Planning a New Fence

Before visiting the lumber yard, run the numbers so you know exactly how many posts, rails and pickets to buy. Overbuying wastes money; underbuying means a second trip.

Budgeting a Project

Material counts let you price out the project. Multiply the post count by the per-post cost, rails by the per-rail cost, and so on. Add 5-10 percent for waste.

Comparing Fence Styles

Run the same fence length through different styles to see how material counts change. Privacy fences need the most pickets; post-and-rail fences need the fewest parts.

Replacing a Section

If you are repairing a stretch of fence, enter just that section length. The calculator gives you the materials for the repair without redoing the whole fence.

1. Forgetting the End Post

The formula is ceil(length / spacing) + 1, not just the division. Missing the end post leaves the last section unsupported.

2. Ignoring Gate Posts

Each gate needs two posts, one on each side. A common mistake is counting the gate opening as a normal section instead of adding the extra posts.

3. Using the Wrong Picket Width

Standard dog-ear pickets are 3.5 inches wide, not 4 inches. Using 4 inches underestimates the picket count by about 12 percent.

4. Skipping Concrete for End and Gate Posts

Every post needs concrete, not just the line posts. Gate and end posts carry the most load and need it the most.

5. Not Adding Waste Allowance

The calculator gives the exact count. In practice, add 5-10 percent for waste, cuts and damaged pieces.

Material costs vary by region and lumber prices, but the relative cost between styles is consistent.

Budget tip: run the calculator for both privacy and semi-private styles on the same fence length. The gap in a semi-private fence reduces the picket count noticeably, which saves on materials without giving up all screening.

The math is exact for a straight fence run on flat ground with uniform spacing. Real projects almost always introduce variables.

With standard 8-foot spacing, you need ceil(100/8) + 1 = 14 posts for the fence line. Add 2 more posts for each gate opening. So a 100-foot fence with one gate needs 16 posts.

The standard spacing for wood fences is 8 feet on center. Use 6-foot spacing in high-wind areas, for heavy panels or when local codes require it.

The general guideline is at least 2 feet, or one-third of the total post length. In cold climates, check your local frost-line depth and bury posts below it.

About 2 bags of 50-pound quick-setting concrete (such as Quikrete) per standard 4x4 post in a 10-inch hole. Larger posts or deeper holes need more.

Divide the total fence length in inches by the picket width (3.5 inches is standard). For a 100-foot fence: 1,200 inches / 3.5 = 343 pickets. Semi-private fences add a gap between pickets, which reduces the count.

A privacy fence has pickets with no gaps, blocking the view completely. A semi-private fence leaves 1-2 inch gaps between pickets, allowing some airflow and light.

Most fences up to 6 feet use 2 horizontal rails: one near the top and one near the bottom. Fences taller than 6 feet or in windy areas benefit from 3 rails.

Pre-built panels install faster and give a uniform look. Individual pickets let you follow the ground grade on slopes and offer more design flexibility. Panels work best on flat ground with consistent spacing.

Each gate needs 2 posts (one on each side). The calculator adds these automatically. Gate hardware (hinges, latches, frames) is separate and depends on the gate design.

No. The calculator covers structural materials: posts, rails, pickets or panels and concrete. Hardware, fasteners, post caps and gate hardware are project-specific and should be estimated separately.

• Quikrete: Setting Fence Posts (Quikrete; concrete mix guidelines for fence post installation, bag-per-post estimates for standard holes).
• Standard fence construction geometry (Home Depot; general fence building overview including post spacing, rail count and picket layout).
• ICC International Residential Code fence provisions (International Code Council; residential fence code references for height, setback and structural requirements).