How many fence boards do I need?

Fence boards sound simple, but the right number depends on board width, the gap between boards and the fence height. Here's the easy method.

Quick answer

With 14 cm wide boards and a 1 cm gap, you'll need about 7 boards per metre of fence. For a 180 cm tall fence that's 7 boards × 180 cm per metre of run.

How that works out

Boards per metre = 100 cm ÷ (board width + gap). 100 ÷ 15 = 6.7 → round up to 7 boards.

Total boards = boards per metre × fence length in metres.

Add 5 % for waste. Boards that crack on the way home or get end-trimmed add up fast.

Example: a 12 m fence, 180 cm tall

12 m × 7 boards/m = 84 boards at 180 cm. Add 5 % waste and you're at 88. With 14 cm boards that's about 75 linear metres of board total – mix lengths to fit what your supplier stocks.

Common mistakes

  • Forgetting the gap and using nominal board width – the count comes out 5–10 % too low.
  • Buying boards across different batches – colour shifts are obvious over a 12 m run.
  • Not planning end details at corners and gates – they often need extra blocking and narrow rip-boards.
  • Letting the boards touch the ground – fence boards in soil rot quickly. Keep a 5 cm air gap.

Get boards, posts and screws

The calculator works out boards, posts and screws from your fence length and height.

Frequently asked questions

What board width is best?

10–14 cm is common. Narrower boards give a more classic look and are easier to handle solo.

How big should the gap between boards be?

5–10 mm. Wood moves with the weather, so without a gap the boards crush together and the fence bows out.

Do the boards need to be pressure-treated?

Yes for outdoor fencing. Treated softwood lasts 15–20 years. Larch or cedar can be left untreated.

How many screws per board?

2 screws per rail. With 2 rails you'll use 4 screws per board.

Ready to get started?

Create a free account and explore all features with a complete demo project.

No credit card required. Free demo project included.