Fence Calculator
A clear, practical calculator with instant results and an explained formula.
Fence Calculator
How to use this calculator
Enter the values and calculate. Adjust inputs to compare results.
Length ÷ spacing, rounded up, plus one end post.
Informational estimate only. Verify important financial, health, engineering, or regulatory decisions with a qualified professional.
A quick post count—and what it assumes
For one straight fence run, divide the length by the maximum post spacing, round the number of bays upward, and add one end post. A 20 m run with 2.5 m spacing creates eight bays and therefore nine posts. Rounding upward prevents the actual spacing from exceeding the value entered; spreading the posts evenly may make each bay slightly shorter.
Corners, gates and changing ground levels
Real boundaries are rarely one uninterrupted line. Count each run between corners separately because corner posts terminate two directions. Gate posts, end posts, changes in height and bracing points may need different sizes or construction. Sloping ground also affects panel fit: stepped panels and raked fencing do not use dimensions in the same way.
Turning the count into a purchase plan
Mark the boundary and locate services before digging. Confirm whether the entered spacing is measured centre-to-centre and whether proprietary panels impose a fixed bay width. The result estimates post positions only; panels, rails, concrete, caps, fixings and allowance for damaged material must be planned separately.
Lay out bays before digging
Transfer the bay count to a string line and divide the measured run evenly. Check the resulting centre-to-centre spacing against panel widths and maximum structural spacing. Doing this before excavation avoids a narrow final bay and reveals where gate or corner posts replace ordinary positions.
Fence Calculator questions answered
Why does the formula add one post?
A row of bays needs a post at both ends. Eight bays, for example, are bounded by nine posts.
Are corner posts counted twice?
They should not be. Calculate connected runs carefully and count a shared corner post once.
Does the result include gate posts?
Not automatically. Add gate, brace and special terminal posts according to the fence design.
Can posts be placed at the exact entered spacing?
The entered spacing acts as a maximum in this calculation. After rounding the bay count, distribute posts evenly along the measured run.