Calculator · Outdoor builds
Fence Board Calculator
Estimate complete pre-cut fence boards or pickets, posts, rails, waste, and optional entered-material cost.
Fence board calculator
Result
Enter fence dimensions, board or picket spacing, posts, rails, and optional prices.
How it works
This fence board calculator estimates complete finished-height or pre-cut vertical boards or pickets, posts, rails, waste, and optional entered-material cost for one simple straight fence run. It supports metric and imperial inputs and preserves the currency symbol you enter without conversion.
Board/picket quantity is based on fence run, actual board/picket width, and the gap between adjacent pieces. Finished height identifies the pre-cut product but does not change piece count.
Price per finished board/picket means the price of one complete piece supplied at the entered height. Cutting multiple pickets from longer stock is not included. Use post spacing and rail-row inputs that are appropriate for your separately verified design; height does not determine them.
- Boards or pickets = ceiling((fence_length + gap) / (board_width + gap)).
- Finished board/picket height is required project/product metadata for the selected pre-cut piece and visual; it is not a quantity multiplier.
- Posts = ceiling(fence_length / post_spacing) + 1.
- Post bays = posts - 1; equal planning-bay length = fence_length / post_bays.
- Required between-post rail sections = post_bays x rail_rows. Each section is allocated whole to rail stock with saw kerf between retained sections cut from the same stock piece.
- Boards with waste = ceiling(boards x (1 + waste_percent / 100)).
- Rail stock with waste = ceiling(feasible_rail_stock_pieces x (1 + waste_percent / 100)).
- Optional entered-material cost = boards_with_waste x price_per_finished_board_or_picket + posts x price_per_post + rail_stock_with_waste x price_per_rail_piece.
Worked example
For a 20 m fence with complete pre-cut 140 mm boards and 10 mm gaps, the board coverage is 150 mm. Boards = ceiling((20 + 0.01) / 0.15) = 134, regardless of the selected finished height.
With 2.4 m post spacing, posts = ceiling(20 / 2.4) + 1 = 10, giving 9 equal planning bays about 2.222 m long. Two rail rows require 18 between-post sections; 4.8 m stock holds two sections plus a 3 mm internal kerf, so 9 stock pieces are required before waste.
Common mistakes
- Using nominal board width instead of the actual measured board or picket width.
- Forgetting that gaps change the board or picket count.
- Entering a per-metre, per-foot, or longer-stock price instead of the price for one complete board or picket at the entered finished height.
- Treating one straight run as a full fence layout when gates, corners, slopes, steps, and bracing need separate planning.
- Assuming one post spacing works for every fence design, material, site, and local requirement.
Common questions
How many fence boards do I need?
Enter the fence length, actual board or picket width, and planned gap. The calculator estimates boards with ceiling((fence length + gap) / (board width + gap)).
Does this calculator include gaps between boards?
Yes. The gap is included in the board or picket count. Enter 0 if the boards or pickets are intended to touch.
Does finished fence-board or picket height change the quantity?
No. This mode assumes complete pre-cut vertical pieces. Height identifies the product and scales the preview, while fence run, actual piece width, gap, and waste determine quantity.
Can this calculate pickets cut from longer stock boards?
No. It does not allocate vertical pickets from longer stock or include vertical-picket kerf, end trimming, or offcut reuse.
Does this calculator include fence posts?
Yes. It estimates posts as ceiling(fence length / post spacing) + 1 for a simple straight run.
Does this calculator include rails?
Yes. It assumes individual rail sections between adjacent posts, with every rail end or joint supported at a post. Continuous rails spanning multiple bays require a separate layout method and are not modelled.
Does this calculator work for metric and imperial?
Yes. Metric inputs use metres and millimetres. Imperial inputs use feet and inches. Lengths are normalized internally before calculating.
Is this a building code or structural calculator?
No. This is for estimating materials only. Verify structural requirements, safety requirements, post spacing, post depth, bracing, gates, wind exposure, soil, and local building rules before building.