Fence Calculator

How to Calculate Fence Panels, Posts and Materials

Building a fence starts with accurate measurements. Ordering too few panels means a second trip to the supplier; ordering too many wastes money. This guide walks you through the formulas and gives you the reference tables you need to get your materials list right first time.

The Panels-Needed Formula

The calculation is straightforward:

Panels needed = Total fence length (m) / Panel width (m), rounded up

For standard 1.83m (6ft) panels along a 15m boundary:

15 / 1.83 = 8.2 → 9 panels

Always round up. A partial panel gap still needs a full panel. If the remainder is very small (under 0.3m), you can trim a panel to fit, but you still need to buy it.

Standard Fence Panel Sizes

The 1.83m x 1.8m panel is the most popular choice for rear garden boundaries across Europe. Check local planning regulations — some areas restrict fence height to 2m (including any trellis extension) without planning permission.

Post Spacing Guide

The post spacing must match the panel width exactly. Posts that are too far apart leave gaps; posts too close together mean panels will not fit without trimming.

Post Depth Recommendations

The one-third rule is a reliable minimum: bury at least one-third of the total post length. Wind loading increases dramatically with fence height, so taller fences in exposed positions should use deeper posts and more concrete. Use our concrete calculator to work out the exact volume if you are mixing standard concrete instead of using Postcrete bags.

Fence Types at a Glance

Closeboard fencing is the most durable option and allows individual boards to be replaced without removing the entire panel. Lap panels are cheaper but tend to blow out in strong winds because the solid face acts as a sail. Building a deck at the same time? Our decking calculator covers boards, joists, and screws for the perfect garden combo.

Complete Materials Checklist

For a 10m fence with 1.83m x 1.8m lap panels:

• Panels: 6 (10 / 1.83 = 5.46, rounded up)
• Posts: 7 (panels + 1)
• Postcrete: 7 bags (1 per post)
• Gravel boards: 6 (one per panel, protects the base from rot)
• Panel clips or nails: 12 pairs (2 per panel)
• Post caps: 7 (keeps rain out of the end grain)
• String line: 1 (keeps posts aligned during installation)

Always buy 10% extra timber to account for defective boards and site adjustments. Having spares on-site saves time and avoids delays. To protect your new fence from the elements, check our exterior paint calculator for fence paint and stain estimates.

How Much Does a Fence Cost?

Fence costs depend on the fence type, boundary length, ground conditions, and whether you install it yourself or hire a contractor. Below is every cost component so you can budget accurately before buying materials.

Cost per Metre Breakdown

What makes up the per-metre cost for a standard 1.8m-high lap panel fence:

Labour is the single largest cost. If you have basic DIY skills and a free weekend, installing the fence yourself roughly halves the total price.

Cost by Fence Type (Material vs Installed)

DIY vs Professional: Total Project Cost

Hidden Costs to Budget For

Many fence quotes cover only panels, posts, and installation. Watch for these extras:

1. Old fence removal — EUR 5-10 per metre if the contractor removes and disposes of the old fence.
2. Concrete post bases — EUR 8-15 per post if upgrading from Postcrete to full concrete foundations.
3. Stepped panels on slopes — 10-20% premium because each panel must be individually cut and fitted.
4. Gate — A matching side gate costs EUR 60-150 plus EUR 20-40 for hinges and a latch.
5. Access difficulty — Narrow side passages or rear gardens with no vehicle access add EUR 100-300 for manual handling.

When to Repair vs Replace

If the posts are solid and vertical, replacing individual panels is always cheaper than a full rebuild. Once posts lean or rot at ground level, the entire run usually needs replacing because the concrete foundations have failed.