Free Fence Calculator (+ Guide)

What is a fence calculator?

A fence calculator turns a fence's length into the posts, rails and pickets it takes.

This one also counts the concrete and gravel for the post holes.

What QUIKRETE says about post holes

QUIKRETE's Setting Posts guide makes the hole 3 times the post's width, and a third of the post's length deep, plus 6 inches for a gravel base.

The concrete goes in up to 3 to 4 inches below the top. For a post that holds up a structure, like a deck, the guide takes the hole at least 6 inches below the frost line.

The Fast-Setting Concrete Mix data sheet gives about 0.375 cubic feet a 50 lb bag.

A worked example

Here's the example the calculator loads: 100 feet with posts 8 feet apart, 2 extra posts, 2 rails a section, and 8-foot 4×4 posts.

100 ÷ 8 = 12.5, so 13 sections and 14 posts, plus 2 = 16 posts and 26 rails. Each hole is 10.5 inches across and 38 inches deep, and takes about 3.3 bags, so 54 bags in all.

With 5.5-inch pickets and half-inch gaps, the fence takes 200 pickets.

Mistakes to avoid

These are the slips that come up most.

• Forgetting the post at the end of the run
• Counting a gate opening as fence
• Digging a hole too narrow for the concrete around the post

Who is the fence calculator for?

It's for anyone building or replacing a fence, and these tools help around it.

• Concrete calculator – for a slab or footing
• Gravel calculator – for a path along the fence
• Square footage calculator – for the yard inside it

Count the posts and the bags first, and the fence goes up in one trip.