Fence Calculator

The fence calculator sizes posts, pickets, rails, concrete, and total material cost for a fence built from one or more straight sections, each with its own length and height. Costs are computed per unit and summed into a single material estimate that includes an adjustable waste factor.

• Sections. Each straight run of fence is its own section with independent length and height, so a property line with corners or grade changes is modeled as several sections rather than one average figure.
• Post spacing. The on-center distance between posts, defaulting to 8 feet, standard for most residential wood fences. Narrower spacing, around 6 feet, suits an enclosure needing more rigidity; wider spacing, 10 to 12 feet, suits a long agricultural run.
• Post width. Defaults to 3.5 inches, corresponding to a nominal 4x4 post; non-standard post stock changes this figure.
• Post depth. Auto mode sets depth at one-third of the above-ground height plus 6 inches, a common building guideline; manual mode takes an exact depth instead.
• Picket width and gap. Default to 3.5 inches and 1.75 inches, producing a standard dog-ear picket fence look; wider boards or gaps give a more open or decorative style.
• Rails per section. Two horizontal rails are standard for fences under 6 feet; three rails are common for taller fences.
• Gates. A gate count and width subtract the gate openings from total fence length before picket and post counts are computed, so a gated section does not overcount material for the opening.
• Pricing. Rail cost is priced per standard 8-foot board; concrete is priced per bag, at a specified number of bags per post.
• Waste factor. A percentage applied to the material subtotal to account for cuts, mistakes, and damaged stock.

Numeric fields accept decimals (6.5), fractions (3/4), and mixed numbers (5 1/2); dollar signs and commas are stripped automatically. Settings holds the waste factor and a step-by-step formula display.

Fence projects range from a single backyard boundary to multi-section perimeter enclosures with gates, and material estimates vary significantly with dimensions and local pricing. The scenarios below illustrate how to apply the fence calculator to common fencing situations.

• Backyard Privacy Fence: Four sections matching each property line, at 6 feet high with three rails per section, total into a single lumber order with the correct waste buffer for posts, pickets, and rails.
• Front Yard Picket Fence: A shorter height of 3 or 4 feet with wider picket gaps gives a decorative look; two rails instead of three lowers material further, and the total cost compares against pre-assembled panel alternatives.
• Dog Run or Pet Enclosure: A small rectangular perimeter with one gate, post spacing tightened to 6 feet, and three concrete bags per post gives a sturdier, more stable enclosure.
• Agricultural or Ranch Fencing: Long straight runs of 100 feet or more per section, with post spacing widened to 10 or 12 feet and wider boards or horizontal slats entered in the picket width and gap fields, reduce both post and picket counts.
• Contractor Bidding: Client property dimensions priced against current supplier rates generate a material cost summary; a waste factor raised to 15 percent covers complex layouts with multiple angles or cuts.
• Slope and Terrain Planning: A hillside fence broken into shorter sections that follow grade changes, each with its own length and height, accounts for stepped or racked panel layouts across uneven terrain.
• HOA or Permit Compliance: Post spacing, fence height, and total linear footage check against local building codes or homeowner association requirements before materials are purchased.
• Partial Fence Repair: Only the damaged sections, rather than the full perimeter, produce an accurate material list for the repair scope without overordering supplies.