Fence Panel Calculator — Panels, Posts & Fittings

Our fence panel calculator divides your total fence run length by the panel width to determine the number of panels needed. The number of posts is always one more than the number of panels, as each bay requires a post on either side. Building close board fencing from individual featheredge boards instead of pre-made panels? Use our close board fencing calculator to work out how many fence slats you need.

The formula

Panels = Fence length ÷ Panel width (rounded up)
Posts = Panels + 1
Post length = Panel height + 600mm (burial depth)

For example, a 10m fence run with standard 1.83m panels: 10 ÷ 1.83 = 5.46, rounded up to 6 panels. You would need 7 posts, each at least 2.43m long (1.83m panel + 0.6m burial).

The count assumes each bay is spaced at the panel width and that every run starts and ends with its own post (posts = panels + 1) — the standard UK merchant convention. Where a run butts up against a wall or an existing post at one end, subtract one post from the total.

Postcrete quantities

Postcrete (fast-setting post mix) is estimated at 2 bags of 20kg postcrete per standard 100×100mm timber post set in a roughly 200–250mm wide × 600mm deep hole (about 1.5 bags for a lighter 75×75mm post, around 3 bags for a heavier concrete post). The estimate adds one bag for fences 2m or taller. Because a hole’s volume scales with its depth and width, the calculator multiplies the bag count by your chosen burial depth — a 1000mm-deep hole needs about two-thirds more postcrete than the 600mm reference hole, and a wider 300mm hole roughly 3 bags rather than 2. For very loose or sandy soil, allow an extra bag per post. These figures are merchant rules of thumb — always check the bag’s coverage and your actual hole size.

UK panel fencing tips

• Standard UK fence panels are 1.83m (6ft) wide — this is the most common size
• Always use gravel boards to protect panels from ground contact and rot
• Concrete posts last longer than timber but cost more upfront
• Check your boundary line before starting — the posts should be on your side
• In exposed locations, consider using concrete posts for extra wind resistance