bdevy.

Fencing & decking

Fence Concrete Calculator

Concrete for fence post holes, per post and for the whole run.

Your numbers

in
ft
in
$

Result

60 lb bags total 49
Bags per post 2.4
Concrete volume 21.7 Cubic feet
Estimated cost $303.80
About 2.4 bags per post, 49 bags for all 20, roughly $303.80.

The post displaces concrete, which is why the post size is subtracted. Fast-setting post mix is poured dry into the hole with water added on top and does not follow the same yield, so check the bag if you are using it.

Get a Free Business Audit

Questions

About this calculator

How wide should the hole be?

About three times the post width, so a 4 inch post wants a 10 to 12 inch hole. Narrower gives the concrete too little grip on the soil.

Should concrete come above ground level?

Crown it slightly above grade and slope it away from the post. Concrete finishing below grade collects water against the timber, which is exactly where posts rot.

The formula

concrete per post = hole volume - post volume; bags = total / 0.45 cubic feet

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.

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.