How to use
- Measure a single straight run and enter its above-ground height.
- Choose maximum section spacing, then measure a picket's actual width and the desired gap.
- Leave rails blank for the height-based planning default, or enter the rail count in your design.
How the estimate is calculated
Sections = run length ÷ maximum spacing, rounded up. An open straight run needs one more post than sections. Rails = sections × rails per section. Pickets = run length in inches ÷ (picket width + gap), rounded up. These are single-layer counts without a waste allowance.
Example: a 100 ft run, 6 ft high, with maximum 8 ft spacing needs 13 sections and 14 posts. The height-based default is 3 rails, so allow 39 rails. Pickets 5.5 in wide with no gap give 1,200 ÷ 5.5, rounded up to 219 pickets.
Typical layout assumptions
| Setting | Planning value | Authority |
|---|---|---|
| Maximum section spacing choices | 6–8 ft | Typical planning practice |
| Rails at heights through 4 ft | 2 per section | Editable planning assumption |
| Rails above 4 ft | 3 per section | Editable planning assumption |
No authoritative wood-fence spacing or rail standard was available for review. These figures describe the calculator's starting assumptions. Confirm member sizes, rail attachment, and post layout for your chosen fence system.
Gates, corners, and overlapping boards
A board-on-board layout overlaps its pickets and needs a separate coverage calculation. It cannot be modeled by a negative gap. Gates need their own framing, hardware, and supporting posts; remove the gate opening from the ordinary fence run and make a separate gate list. When combining runs at a shared corner, count the shared post only once. Post depth and hole concrete are outside this page's takeoff.
Common mistakes
- Counting the same corner post in two adjacent runs.
- Using nominal lumber width in place of measured coverage.
- Assuming rail count also supplies rail stock lengths, connections, and offcuts.
- Using the straight-run post total for a closed enclosure with no adjustment.
Sources
The section-spacing and rail defaults are typical planning assumptions for this estimate; no authoritative wood-fence source was available for review. Picket counts follow the dimensions you enter. NIST's exact inch relationship is used for unit conversions.
Related calculators
- Concrete Calculator — volume for separately measured post holes
- Board Foot Calculator — volume of a prepared lumber list
Frequently asked questions
Does the count include a gate?
No. Calculate ordinary fence runs excluding gate openings, then add the gate posts, framing, and hardware from the gate design.
Can I estimate board-on-board fencing?
This model covers a single picket layer. Overlapping boards need their own exposed-width calculation and generally more pieces.
Why are there more posts than sections?
An open straight run has a post at both ends, with intermediate posts shared by adjacent sections.
How many rails does the automatic setting use?
It uses two rails per section through 4 ft high and three above 4 ft. These are typical planning figures you can override.
Are post holes and concrete included?
They are excluded. Establish the required depth and hole dimensions separately before estimating concrete.