Concrete Per Fence Post Calculator

Calculate the concrete to set a fence post, the hole volume, cubic feet and how many 80, 60 or 50 lb bags you need per post and for the whole fence.

Read the guide: How Much Concrete Per Fence Post?

Concrete per post

Bags per post

3

1.35 ft³ of concrete per hole

Bags for all posts
42
Total concrete
18.89 ft³

That is the hole volume minus the post. Mixing a touch extra is wise, concrete settles and a part-filled last bag is normal.

For fast-setting or gravel-base methods the volume differs. Always set below your local frost line.

How it works

  1. 1

    Size the hole

    Enter the post width, hole diameter and depth. A good rule is a hole three times the post width.

  2. 2

    Pick a bag

    Choose the bag size you are buying, 80, 60 or 50 lb.

  3. 3

    Get the bags

    See the cubic feet and bag count per post, then for every post in the run.

Instant & 100% private — nothing is uploaded

Every calculation runs locally in your browser. The income, balances and goals you enter stay on your own device and are never sent to a server — nothing is stored, logged or shared.

Frequently asked questions

How much concrete per fence post?
It is the hole volume minus the post. A 4×4 post in a 12-inch hole dug 2 ft deep takes roughly 1.3 cubic feet, about three 80 lb bags. Bigger holes need more.
How deep should the hole be?
Set posts about a third of their above-ground height deep, and always below your local frost line. Two to three feet is common.
Which bag size is best value?
An 80 lb bag yields about 0.6 ft³, a 60 lb about 0.45, a 50 lb about 0.375. Fewer big bags usually means less mixing, the calculator shows the count for each.
Are these numbers exact?
They are close planning estimates, not a substitute for a contractor takeoff. Real quantities depend on your terrain, post spacing, waste and local building code, so buy a little extra and confirm against your supplier.
Is my fence design sent anywhere?
No. Everything runs in your browser. The layout, lengths and prices you enter stay on your device, nothing is uploaded, logged or stored, and it all clears when you close the tab.