Worked example · Outdoor
Fence Calculation Example for 100 Linear Feet
Calculate panel positions, posts, waste panels, and whole-unit purchasing for one straight 100 ft fence run using 8 ft panels.
Introduction
This example uses the Fence Calculator’s prefabricated-panel mode for one straight 100 ft net run. The run contains no gate, corner, or separate opening; those conditions are not supported as automatic deductions and would require a different dimensioned layout.
With an actual panel width of 8 ft, 100 ÷ 8 = 12.5 exact panel positions. The calculator rounds layout positions to 13 sections and assigns 14 posts—one at every boundary. A 10% example waste input raises purchase quantity to 14 panels but does not create extra layout posts.
In this guide
- Divide the net straight run by actual panel width
- Round 12.5 positions up to 13 installed sections
- Use sections + 1 for 14 posts in this simple run
- Distinguish 13 layout panels from 14 panels purchased with waste
Project setup
Example at a glance
These are the exact values used in the article, diagram, formulas, chart baseline, and calculator result.
- Mode
- Prefabricated panels
- Net straight run
- 100 ft
- Panel width
- 8 ft
- Illustrative actual module; verify the selected panel.
- Waste allowance
- 10%
- Applied to panels purchased, not posts.
- Gates / corners
- None in this scenario
- Handle these as explicit layout events outside the simple formula.
Start on site
Measurements you need
Record dimensions on a sketch and label every unit. Separate areas whenever shape, depth, product, or installation condition changes.
Use net infill length
The full 100 ft is panel infill because the scenario has no gate or opening. If a gate exists, establish the remaining straight run and its gate-post arrangement before entering a number.
Use actual panel module
Eight feet is the selected panel width. Advertised or nominal dimensions should be checked against the real installed module.
Draw section boundaries
Thirteen panel positions create fourteen boundaries from the first end to the second. That is why a simple independent straight run has one more post than sections.
Keep spare panels separate
The 10% allowance is applied to exact panels before purchase rounding. A spare panel is material inventory; it is not another installed section and does not automatically require a post.
- Mode
- Prefabricated panels
- Net straight run
- 100 ft
- Panel width
- 8 ft
- Waste allowance
- 10%
- Gates / corners
- None in this scenario
Units used in this method
- Exact panel positions = 100 ft ÷ 8 ft = 12.5
- Layout sections = ceil(12.5) = 13
- Straight-run posts = 13 + 1 = 14
Core arithmetic
The formula
Purchase panels are calculated separately: ceil[(100 ÷ 8) × 1.10] = 14. Layout capacity is 104 ft, so the last installed section may require project-specific adjustment.
Base formula
sections = ceil(100 ÷ 8) = 13; posts = 13 + 1 = 14
Repeatable workflow
Step-by-step calculation method
Divide run by panel width
The exact result is 12.5 panel modules.
Round installed sections
A half panel position still needs material, so the layout uses 13 sections. Their nominal capacity is 104 ft.
Count simple-run posts
13 panel spaces have 14 boundaries, producing 14 posts in this straight independent run.
Apply the panel allowance
12.5 × 10% = 1.25 additional exact panels. Total exact purchase demand is 13.75.
Round purchase panels
The calculator rounds 13.75 upward to 14 panels. Posts remain 14 because they come from the installed layout, not spare stock.
Calculation flow
- 1. Measurements100 ft net run · 8 ft panel module
- 2. Base quantity12.5 exact · 13 layout sections
- 3. Adjustments13.75 exact panels at 10% waste
- 4. Purchase quantity14 panels · 14 layout posts
Every transition shown
Complete calculation with substituted values
Example at a glance: one straight 100 ft run, 8 ft panels, no gate or corner, and 10% panel waste.
- 1.100 ÷ 8 = 12.5 exact panels
- 2.ceil(12.5) = 13 installed sections
- 3.13 + 1 = 14 posts
- 4.12.5 × 1.10 = 13.75 exact purchase panels
- 5.ceil(13.75) = 14 panels to buy
Layout: 13 sections and 14 posts. Purchase: 14 panels after the example allowance. Posts equal installed sections plus one; they do not equal spare-inclusive purchase panels plus one.
Formula data visualization
Chart assumption: One straight 100 ft net run with no gates, corners, or shared posts.
Actual panel width
| Actual panel width | Whole layout units |
|---|---|
| 6 ft | 17 sections · 18 posts |
| 7 ft | 15 sections · 16 posts |
| 8 ft · baseline | 13 sections · 14 posts |
| 10 ft | 10 sections · 11 posts |
Use judgment openly
Panel width changes two discrete counts
The chart changes only actual panel width and sets waste to zero to isolate layout. Each result rounds exact panel positions upward, then adds one post for the simple run.
A smaller final bay, cut panel, slope, gate, corner, or shared post requires a drawn layout. The arithmetic does not decide whether a product can be trimmed or structurally installed in that arrangement.
Check before ordering
Common calculation mistakes
Rounding 12.5 down
Twelve 8 ft panels cover only 96 ft, leaving part of the run unfilled.
Using purchased panels to count posts
Posts follow 13 installed positions; the spare-inclusive panel purchase is separate.
Subtracting a gate without laying out posts
A gate changes infill length and terminal conditions, so it needs explicit planning.
Applying panels + 1 to multiple runs
The shortcut applies only to one simple independent straight run.
Before the order
Field check before purchasing
Mark the actual endpoints and verify the 100 ft is net infill length. Identify every gate, corner, grade change, terminal, and obstacle before treating the run as simple.
Verify panel module and whether the final section can be adjusted. Confirm post system, structural requirements, property information, and utilities separately.
What the number cannot tell you
Practical limits of the result
- This example estimates fence panels quantity from the stated geometry. It does not design the assembly, verify site conditions, select a product, or replace project documents.
- The allowance is an explicit example input, not a universal recommendation. Change it to match the layout, product, field conditions, supplier guidance, and the amount of usable offcut or reserve.
- Confirm measured dimensions and purchasing units before ordering. Supplier minimums, package contents, stock lengths, delivery constraints, and product data can change the final transaction.
Common questions
Fence Calculator example FAQ
Why are there 14 posts for 13 sections?
A straight line of 13 spaces has a boundary at both ends, producing 14 post positions.
Why are 14 panels purchased but only 13 installed?
The 10% example allowance is applied to exact panel demand and whole-panel rounding produces one spare-inclusive purchase unit.
Does this include a gate?
No. The 100 ft is a net straight infill run with no gate in the scenario.
Can the last panel be cut?
The calculator does not verify that. Check the selected system and create a dimensioned layout.
Continue planning