CalcReed

Home & DIY calculator

Fence Calculator

Enter your fence run and panel width to get panels, posts, and postcrete bags in one result.

Your measurements

Metric + imperial

How this calculator works

Panels = round up(run length / panel width). Posts = panels + 1. Postcrete bags = round up(net hole volume x posts / bag yield), where net hole volume is hole volume minus the post volume it displaces.

Worked example

A 12 m run with 1.8 m panels needs 7 panels and 8 posts. With 30 cm x 60 cm deep holes and 10 cm posts, that is 15 bags of postcrete.

Assumptions to check

  • The run is straight, with one post per panel plus one closing post (no corners or gates counted separately).
  • Posts are treated as square in cross-section, centered in a round hole.
  • Postcrete yield varies by brand; use the figure on the bag.

Read the calculation and QA methodology →

Common questions

FAQ

What is postcrete?

A fast-setting, pre-mixed concrete sold in bags for setting fence and deck posts without separately mixing sand, aggregate, and cement.

Do corners or gates change the post count?

Yes - this calculator assumes a single straight run. Add extra posts manually for corners, gate posts, or return runs.

Can I skip the concrete and use a post spike instead?

Yes. Set post width to 0 to model a footing-only hole, or ignore the postcrete output if you are using metal post supports instead.