How much clearance should there be under the fence?

An inch or two is usual, so the boards are not wicking moisture out of wet soil and so the fence line can follow small dips in the ground. It also means the picket length you buy is roughly the fence height rather than the height plus the gap — worth getting straight before you order a few hundred boards.

What size posts do I need?

A 4×4 handles most residential line posts. Corner and gate posts carry more load, and many builders step up to a 6×6 or set them deeper. The calculator counts each type separately so you can order the right mix rather than a single number.

How long should the pickets be?

Picket length is your fence height, give or take the ground clearance you want underneath. Most people leave an inch or two so the boards are not sitting in wet soil. The count here is per picket, so the length is your choice at the merchant.

Cedar or pressure-treated pine?

Cedar costs more per foot and resists rot naturally; pressure-treated pine is cheaper and chemically protected. The material count is identical either way — only the price changes, which is why the cost estimate and the quantity calculation are kept separate here.

Fence Ledger

Wood Fence Calculator

The complete material list for a wood privacy fence — and the lumber measurements that make it come out right.

Units

Shape

Fence length

Height

Gates

Picket gap

Advanced options

These are typical values, not requirements. Post depth in particular is governed by your local frost line and building code — check before you dig.

Post spacing

Gate width

Hole diameter

Hole depth

Gravel base

Bag yield

Waste allowance

Posts

Sections

Pickets

336

Concrete

35 bags

Estimated cost

Materials only (DIY)

$1,400 – $3,600

Professionally installed

$3,950 – $8,850

National planning ranges compiled from published US construction cost guides, last checked September 2026 (confidence: medium-low). Prices vary sharply by region, season and contractor. These are estimates for planning, not quotes.

Sources: homeguide.com, calcsummit.com, angi.com, ergeon.com, homewyse.com

Shopping list

Bill of materials for this fence
Material	Size	Quantity
Posts	4x4	21
Rails incl. waste	2x4	63
Pickets incl. waste	1x6	336
Concrete mix		35bags
Gravel		8bags
Exterior screws		≈2,200
Walk gate kit		1

Why these numbers

How we got the section count

Run 1: 146 ft ÷ 8 ft = 18.25, rounded up to 19 sections

How we got the post count

3 posts are fixed by the shape itself
2 at the open ends
1 carrying a gate
18 line posts spaced between them
21 posts in total

How we got the picket count

Each picket covers 5.5 in plus a 0.25 in gap, so they repeat every 5.75 in
146 ft of fence needs 305 pickets
Plus 10% for offcuts, rounded up to 336

How we got the concrete

Each 10 in hole is 30 in deep, less 4 in of gravel base, leaving 26 in of concrete
The 4x4 post itself takes up part of that, so each hole needs the remainder
Across 21 posts
Divided by the 0.6 cu ft a bag yields: 34.91, so buy 35 bags

Nominal size is not actual size

A picket sold as a "1×6" is 5.5 inches wide. A "4×4" post is 3.5 inches square. A "2×4" rail is 1.5 by 3.5. The names come from the rough-sawn dimension before the board was dried and planed, and they stuck.

This matters more than it sounds. Counting pickets at 6 inches instead of 5.5 undercounts by about 9% — nine boards short on a hundred-foot fence, found out when you run out with two sections to go. This calculator uses actual dimensions throughout and shows the nominal name only on the shopping list, where it is what the tag says.

Rails follow height, not preference

A four-foot fence typically takes two rails, a six-foot fence three, and an eight-foot fence four. The rule is about keeping the pickets supported along their length rather than about strength at the post.

The count here follows the height you enter rather than being a number you have to remember to change. If your design differs, the rail count is derived and the material list follows.

Where the waste allowance goes

Ten percent is added to pickets and rails, because both are cut to fit and produce offcuts, and because a proportion of any bundle has a knot or a split in the wrong place.

Nothing is added to posts. You need a post at a location or you do not, and there is no such thing as a tenth of a post. Concrete carries no percentage either — rounding the bag count up is already the allowance, and adding one on top would charge you for the same margin twice.

Common questions

How much clearance should there be under the fence?: An inch or two is usual, so the boards are not wicking moisture out of wet soil and so the fence line can follow small dips in the ground. It also means the picket length you buy is roughly the fence height rather than the height plus the gap — worth getting straight before you order a few hundred boards.
What size posts do I need?: A 4×4 handles most residential line posts. Corner and gate posts carry more load, and many builders step up to a 6×6 or set them deeper. The calculator counts each type separately so you can order the right mix rather than a single number.
How long should the pickets be?: Picket length is your fence height, give or take the ground clearance you want underneath. Most people leave an inch or two so the boards are not sitting in wet soil. The count here is per picket, so the length is your choice at the merchant.
Cedar or pressure-treated pine?: Cedar costs more per foot and resists rot naturally; pressure-treated pine is cheaper and chemically protected. The material count is identical either way — only the price changes, which is why the cost estimate and the quantity calculation are kept separate here.