Fence Calculator

Estimate fence panels, posts, pickets, rails, concrete bags, fasteners, gates, waste, and material cost.

How the fence estimate works

Gate openings are subtracted from the measured fence length. The remaining length is divided by the selected panel width or post spacing and rounded up to whole sections. Posts include one extra post to end each separate run and one additional post for each gate, following the planning method in the Lowe’s fence worksheet.

Net fence: total length − (gates × gate width)
Panels: ceil[net fence ÷ panel width]
Posts: panels + separate runs + gates

Panels or individual pickets

The panel total is for preassembled sections. The picket and rail totals are an alternative component-build estimate, not items to buy in addition to panels. Pickets use actual width plus the chosen gap and the visible waste allowance. Rails equal whole fence sections multiplied by rails per section. Manufacturer instructions govern exact spacing, brackets, partial panels, slopes, and gate openings.

Concrete-bag calculation

Concrete volume is the cylindrical hole volume minus the square post volume within the hole. Bags are rounded up using 0.375 cubic foot yield per 50-lb bag, as published by QUIKRETE for Fast-Setting Concrete Mix. Actual holes, soil, frost depth, drainage gravel, post shape, and product yield can change the quantity.

Worked example

For 120 linear feet with one 4-ft gate, one run, and 8-ft sections, the net fence length is 116 ft. Purchase 15 panels and plan for 17 posts. With 5.5-in pickets, no gap, 10% waste, and three rails per section, the alternative component-build estimate is 279 pickets and 45 rails. Twelve-inch-diameter holes 36 inches deep around 3.5-inch square posts require about 96 50-lb concrete bags.

Before purchasing

Measure and calculate each fence run separately when exact partial-panel placement matters.
Confirm property lines, underground utilities, permits, easements, frost depth, wind exposure, pool-barrier rules, and local fence requirements.
Use the selected manufacturer’s post spacing, gate opening, bracket, fastener, and installation instructions.
Corner, end, and gate posts may require different sizes or reinforcement; this calculator reports a combined planning count.

Technical references: Lowe’s preassembled-panel fence worksheet, Lowe’s post-layout guidance, and QUIKRETE Fast-Setting Concrete data sheet.

Fence calculator FAQ

How many posts do I need?

For one straight run of preassembled panels, start with one more post than panels. Add another post for each gate. Multiple disconnected runs each need their own ending post.

Are panels and pickets added together?

No. Choose either the panel-build quantity or the component-build picket and rail quantities for purchasing.

How far apart should fence posts be?

Common planning spacing is often 5 to 8 feet, but exact spacing depends on the selected panel or rail system, attachment method, slope, loads, and local requirements.

Does the estimate include gate hardware?

No. Gates are counted, but hinges, latches, stops, drop rods, reinforcement, and specialty gate posts must be selected for the actual gate system.