Fence Board Calculator
How many fence boards, rails and posts for any board width, gap or board-on-board style.
Enter the fence length and height, the board size and how the boards go on. The calculator uses the real dressed width of the board (a 1x6 is 5.5 in wide), counts the boards and adds your waste, then lays out the posts, rails and fasteners and totals the board feet.
0 for a privacy fence
3 for a 6 ft fence
Calculation Results
Nominal sizes are not real sizes: a 1x6 board is 5.5 in wide under the American Softwood Lumber Standard, which is why counting on 6 in runs short.
📱 More free Android calculators
Fencing, decking and drywall estimators from Dixon App Studio — all free on Google Play.
Smart Fencing CalculatorThis site
Fence posts, pickets, rails, concrete, gates and total project cost.
Get it on Google PlaySmart Decking Calculator
Deck boards, joists, footings, railings and material cost estimates.
Get it on Google PlaySmart Drywall Calculator
Drywall sheets, mud, tape, screws and finishing cost estimates.
Get it on Google PlaySod Calculator: Mulch, Topsoil
Sod pallets, mulch, topsoil and seed for the yard around your new fence.
Get it on Google PlayGravel & Stone Calculator
Gravel, crushed stone and base rock in tons and cubic yards.
Get it on Google Play🔧 Recommended Fencing Tools & Supplies
Disclosure: As an Amazon Associate I earn from qualifying purchases.
VEVOR Post Hole Digger,52cc 1450W Auger Digger,Gas Powered Earth Digger with Two Drill Bit 6''& 10''and 3 Extension Rods,for Farmland,Garden and Plant,EPA Certification,Black+Orange+White
$159.90
Check price on Amazon
H.B. Fuller Fast 2K Post Anchor Mix | Expanding Composite Footing Compound (Fence, 1)
$27.99
Check price on Amazon
Ready Seal Exterior Wood Stain | Semi-Transparent Oil-Based Formula | Professional Grade Stain and Sealer in One | Ideal for Decks, Fences, Pergolas, Wood Siding & More | Gallon | Dark Walnut
$39.99
Check price on AmazonPrices as of Sep 30, 2026, 4:36 AM UTC. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
🛠️ How This Calculator Works
Each board plus its gap takes up a fixed width along the fence. Divide the fence length in inches by that width and round up. For board-on-board, a back board and a front board lapping it on both sides together cover two board widths minus two overlaps, so the pairs are counted and doubled. Posts go at your spacing, each section gets the number of rails you choose, and the boards are cut from the shortest stock length that reaches the fence height.
📐 Formula
Side by side: boards = ceil(length × 12 ÷ (dressed width + gap)) · Board-on-board: boards = 2 × ceil(length × 12 ÷ (2 × width − 2 × overlap)) · Sections = ceil(length ÷ post spacing) · Posts = sections + 1 · Rails = sections × rails per section · Board feet = 1 × nominal width × length ft ÷ 12📝 Example Calculation
100 ft of 6 ft privacy fence, 1x6 boards tight together, posts every 8 ft, 3 rails: Boards = ceil(1,200 ÷ 5.5) = 219 (230 with 5% waste) Sections = ceil(100 ÷ 8) = 13 → 14 posts Rails = 13 × 3 = 39 2x4x8 Fasteners = 219 × 3 × 2 = 1,314 Board feet = 230 × 3 = 690 bf of boards (with waste)
💡 Pro Tips from Fence Builders
- Pine and cedar boards shrink across their width as they dry, so boards butted tight when wet open small gaps later. Leave about 1/4 in if the boards are dry.
- Measure a few boards before you trust 5.5 in — rough-sawn cedar can be wider, and warped boards eat width.
- Use a spacer block cut to the gap so every board goes on the same, and check plumb every few boards.
- Buy the waste allowance: split ends, knots through the edge and cuts at gates and slopes use it up.
- Hot-dipped galvanised or stainless fasteners stop black streaks on cedar and redwood.
❓ Frequently Asked Questions
How many fence boards do I need?
Divide the fence length in inches by the real board width plus any gap. A 1x6 is 5.5 in wide, so 100 ft of fence with the boards tight together needs 1,200 ÷ 5.5 = 219 boards, about 2.2 per foot. Add 5 to 10% for waste.
How many fence boards are in an 8 ft section?
An 8 ft section is 96 in. With 1x6 boards (5.5 in) tight together that is 96 ÷ 5.5 = 17.5, so 18 boards. With a 1/2 in gap it is 96 ÷ 6 = 16. With 1x4 boards (3.5 in) and no gap it is 28.
What is the actual width of a 1x6 fence board?
5.5 in wide and 3/4 in thick when dry, under the American Softwood Lumber Standard (PS 20). A 1x4 is 3.5 in, a 1x8 is 7.25 in, a 1x10 is 9.25 in and a 1x12 is 11.25 in. Rough-sawn or green boards can be slightly larger.
How many boards for a board-on-board fence?
About twice as many as the gaps between them suggest. With 1x6 boards lapping 1 in on each side, every back-and-front pair covers 2 × 5.5 − 2 × 1 = 9 in, so 100 ft of fence needs 134 pairs, or 268 boards — about 22% more than a tight side-by-side fence.
How many rails does a fence need?
Two rails is common for fences up to about 4 ft, and three for a 6 ft privacy fence so the boards cannot bow in the middle. Taller fences or wide boards that cup benefit from a fourth. Each rail spans one section between posts.
How many board feet are in a fence board?
Board feet use the nominal size: thickness × width × length in feet ÷ 12. A 1x6 that is 6 ft long is 1 × 6 × 6 ÷ 12 = 3 board feet, and a 2x4 that is 8 ft long is 5.33 board feet.
📬 Free Fencing Cost Guide
Get weekly fencing tips, material cost updates, and exclusive calculator guides — straight to your inbox.
No spam, ever. Unsubscribe anytime.
📝 Related Articles
🧮 You May Also Need
Related calculators for your fencing project
Fence boards per 8 ft section
Boards for one 96 in section, using the dressed widths in the American Softwood Lumber Standard (PS 20).
| Board | Actual width | No gap | 1/2 in gap | Board-on-board, 1 in lap |
|---|---|---|---|---|
| 1x4 | 3.5 in | 28 | 24 | 40 |
| 1x6 | 5.5 in | 18 | 16 | 22 |
| 1x8 | 7.25 in | 14 | 13 | 16 |
Fence boards for common fence lengths
| Fence length | 1x4, no gap | 1x6, no gap | 1x6, 1/2 in gap | 1x8, no gap |
|---|---|---|---|---|
| 50 ft | 172 | 110 | 100 | 83 |
| 100 ft | 343 | 219 | 200 | 166 |
| 150 ft | 515 | 328 | 300 | 249 |
| 200 ft | 686 | 437 | 400 | 332 |
Related calculators
Picket fences with even gaps are easier in the picket spacing calculator, and horizontal slat fences in the horizontal fence calculator. For the overlapping style there is a dedicated board-on-board fence calculator. Count the concrete for the posts with the fence post concrete calculator, work out the finish with the fence paint calculator, and price the whole job with the fence materials cost calculator.