Fencing & decking
Fence Length Calculator
Works out how much fence you actually need, which is the sides being fenced less the gates.
Result
Measure the actual boundary rather than the plot dimensions. Slopes make the fence longer than the plan shows, and a boundary that is not square catches people out. Confirm the property line before anything is dug.
Get a Free Business AuditHow the calculation works
Add the runs of the sides being fenced and subtract the width taken by gates, since a gate opening is not fence. The arithmetic is simple and the measuring is where the errors are. A boundary is rarely a neat rectangle, sides are often not the same length as the plot dimensions suggest, and a fence that follows a slope is longer than the horizontal distance on a plan. Measuring on the ground along the line the fence will actually take is the only reliable method.
What moves the number
- Whether the ground is level, since a sloping run is longer than its plan dimension.
- Gate widths and how many, as each one removes fence and adds two posts.
- Whether the fence follows the boundary or is set inside it, which changes the run.
- Obstacles such as trees, services and rock, which can force the line to deviate.
Where this one goes wrong
Establish where the boundary actually is before measuring to it. Assumed boundaries are wrong often enough that a fence built on one becomes a dispute, and moving a completed fence is expensive and bad tempered. A survey or existing pins are the answer, and setting the fence slightly inside a known line is a common way to avoid the argument. It is also worth checking local rules and any community restrictions before finalising the run, since permitted height, permitted materials and setbacks from the boundary and from sight lines at corners are all commonly regulated.
Before you quote
- Confirm the boundary from pins or a survey before measuring to it.
- Measure along the ground on sloping runs, not on a plan.
- Check local height, material and setback rules before committing to the line.
Questions
About this calculator
Should I measure the boundary or the fence line?
The line the fence will actually take, on the ground. Plot dimensions and plan measurements do not account for slope, deviations around obstacles, or a fence set inside the boundary. Sloping ground in particular makes the real run longer than the plan distance.
How do I know where my boundary is?
From survey pins or a survey, not from assumption or from where an old fence stood. Existing fences are frequently not on the line. Building on an assumed boundary is how fences become legal disputes, and setting slightly inside a known line is a common way to avoid that.
Do I need permission to build a fence?
Often. Height limits, permitted materials, setbacks from the boundary and sight line restrictions at corners are commonly regulated, and community restrictions can be stricter than the local code. It is worth checking before ordering material rather than after the fence is up.
The formula
fence = run of the sides being fenced - the width taken by gates
Put this calculator on your site
Free to embed. Paste this where you want it to appear. It stays up to date automatically because it loads from BDEVY.
Please keep the attribution line. It is the only thing we ask in return.
How to use this calculator
- Yard length (ft) (ft). Enter your own figure; the page starts at 90 ft.
- Yard width (ft) (ft). Enter your own figure; the page starts at 60 ft.
- Sides to fence. Enter your own figure; the page starts at 3.
- Number of gates. Enter your own figure; the page starts at 2.
- Gate width (ft) (ft). Enter your own figure; the page starts at 4 ft.
- Installed cost per foot ($). Enter your own figure; the page starts at $32.
The result updates as you type, so you can try a figure, see what it does to fence needed, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Yard length (ft) | 90 ft |
| Yard width (ft) | 60 ft |
| Sides to fence | 3 |
| Number of gates | 2 |
| Gate width (ft) | 4 ft |
| Installed cost per foot | $32 |
What comes out
| Result | Value |
|---|---|
| Fence needed main result | 232 |
| Full perimeter | 300 |
| Taken up by gates | 8 |
| Estimated installed cost | $7,885 |
232 linear feet of fence plus 2 gates, roughly $7,885 installed. Gates cost noticeably more per foot than plain fence.
How sensitive the answer is
Holding everything else steady and changing only installed cost per foot, this is what happens to fence needed. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Installed cost per foot ($) | Fence needed |
|---|---|
| $16 | 232 |
| $24 | 232 |
| $32 example above | 232 |
| $48 | 232 |
| $64 | 232 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Yard length (ft) (ft)
- Measured in ft, starting at 90 ft.
- Yard width (ft) (ft)
- Measured in ft, starting at 60 ft.
- Sides to fence
- A number, between 1 and 4, starting at 3.
- Number of gates
- A number, between 0 and 10, starting at 2.
- Gate width (ft) (ft)
- Measured in ft, between 0 and 20, starting at 4 ft.
- Installed cost per foot ($)
- A money amount, starting at $32.
What the results tell you
| Result | What it is |
|---|---|
| Fence needed | The headline result. A number. |
| Full perimeter | A number. |
| Taken up by gates | A number. |
| Estimated installed cost | A money figure. |
Keep going
Related calculators
Estimating is the easy part
The jobs you never hear about cost more than the ones you mis-measure. BDEVY builds the marketing, systems and automation that bring them in.