Home / US calculators / Fencing and decking
Last updated: October 3, 2026
Fence calculator
Work out sections, posts and concrete for a new fence. US units: feet, inches and cubic feet. Results update as you type.
How to use this calculator
Measure the total length of the fence line. Enter the width of your fence sections.
This calculator assumes one straight run. Add an extra post for each corner, gate or change of direction.
How it's calculated
Panels = fence length ÷ panel width, rounded up. Posts = panels + 1 for a straight run. Concrete is posts × bags per post.
Worked example
A 100 ft run with 8 ft sections: 100 ÷ 8 = 12.5, rounded up to 13 fence sections and 14 posts.
Common questions
How many bags of concrete per post?
It depends on the post size, hole size and product. Check the instructions on the bag, which usually state how many bags a typical post needs.
Do I need planning permission or approval?
Rules on fence height and boundaries vary by area. Check with your local council or authority before building.
What if my fence has a gate?
Reduce the length by the gate width and add gate posts separately.