How to Measure for a Fence Panel (UK): Panels and Posts

Quick answer: Standard UK fence panels are 1.83 m (6 ft) wide and come in heights from about 0.9 m to 1.83 m. To measure, take the fence run in metres, divide it by the panel width plus one post width to count panels, and add one post more than panels. Each post needs about 600 mm in the ground.

Measuring for a fence comes down to three numbers: how many panels fit the run, how tall the fence will stand, and how long each post must be. This guide covers all three, with charts for posts and gravel boards and a note on height limits. It is part of our collection of garden and outdoor measuring guides.

Add the panel, the gravel board and the buried depth, then round up to the next stock post length.

Table of Contents

What size is a standard UK fence panel?

The standard UK fence panel is 6 ft wide, which is about 1.83 m. Panels are still named in feet, so you will see “6 × 6”, “6 × 5” and “6 × 4” on the shelf, meaning 6 ft wide by 6, 5 or 4 ft high. The exact millimetre size varies slightly between makers, so check the product listing before you set your posts.

Panel name	Nominal width	Nominal height	Exact imperial equivalent
6 × 3	1.83 m	0.91 m	3 ft = 0.9144 m
6 × 4	1.83 m	1.22 m	4 ft = 1.2192 m
6 × 5	1.83 m	1.52 m	5 ft = 1.524 m
6 × 6	1.83 m	1.83 m	6 ft = 1.8288 m

Gravel boards, the concrete or treated timber strips that sit under a panel to keep it off the soil, are usually the same 1.83 m length and commonly 150 mm (6 in) or 300 mm (12 in) tall. The feet to cm converter handles any other imperial sizes you come across.

What do you need to measure for a fence?

A 20 m or 30 m tape measure for the full run
Two pegs and a builder’s string line to mark the fence line
A spirit level and a straight timber batten for checking slopes
Marker spray or extra pegs to mark post positions
A notebook to record the run length, any corners and any gates

Our guide to reading a tape measure is worth a look if your tape has both metric and imperial markings, since mixing the two is a common source of error on long runs.

How do you measure a fence run?

Stretch a string line along the exact line of the new fence and measure along it from end to end in metres. Then work through these steps.

Confirm the boundary. Check your title plan or agree the line with your neighbour before you measure; a fence a few centimetres over the line can cause disputes.
Set the line. Drive a peg at each end and pull a string tight between them, set where the face of the posts will sit.
Measure the run. Measure along the string from the outer face of the first post position to the outer face of the last. On a slope, measure horizontally, not along the ground.
Note corners and gates. Treat each straight section as its own run. Measure gate openings separately, because gates need their own posts and hardware.
Check the fall. Put a level on a straight batten at intervals, or use a line level on the string, and note how far the ground drops over the run.
Count panels and posts. Use the formula below, then decide where any cut panel will go.

How many fence panels and posts do you need?

Panels = (run length − one post width) ÷ (panel width + post width), rounded up. Posts = panels + 1 for a straight run. With 1.83 m panels fixed between 100 mm timber posts, each bay takes 1.93 m from post centre to post centre.

Seven full bays reach 13.61 m, leaving a 1.29 m gap for a cut panel before the ninth post.

Here is the working for the 15 m run in the plan. (15 − 0.1) ÷ 1.93 = 7.72, so you need 8 panels: 7 full and 1 cut. Seven full bays plus the first post cover 7 × 1.93 + 0.1 = 13.61 m. That leaves 15 − 13.61 = 1.39 m, and once the last 100 mm post is taken off, the final panel must be cut to 1.29 m. You need 9 posts and 8 gravel boards, one of them cut to match.

Slotted concrete posts work slightly differently because the panel slides into a groove in each post, so the spacing depends on the post design. Check the manufacturer’s centre-to-centre figure, or dry-fit a panel before concreting the second post. On any run, add one extra post for each corner that does not share a post, and two for every gate.

How long should fence posts be?

Post length = panel height + gravel board height + depth in the ground, usually 600 mm. Round the answer up to the next stock length, which for timber posts is typically 1.8 m, 2.1 m, 2.4 m, 2.7 m or 3.0 m. Jacksons Fencing, for example, recommends a 600 mm deep hole for its posts and pairs 2.7 m posts with panels between 2.0 m and 2.14 m high.

Panel height	No gravel board	150 mm gravel board	300 mm gravel board
0.91 m (3 ft)	1.51 m → 1.8 m	1.66 m → 1.8 m	1.81 m → 2.1 m
1.22 m (4 ft)	1.82 m → 2.1 m	1.97 m → 2.1 m	2.12 m → 2.4 m
1.52 m (5 ft)	2.12 m → 2.4 m	2.27 m → 2.4 m	2.42 m → 2.7 m
1.83 m (6 ft)	2.43 m → 2.7 m	2.58 m → 2.7 m	2.73 m → 3.0 m

Each cell shows the minimum post length with 600 mm buried, then the next stock length up. Where the minimum is only a few centimetres over a stock length, as with a 6 × 6 panel and no gravel board, some installers use the shorter post and set it a little shallower; others buy the longer post and trim the top. Spare length above the panel can be cut off or finished with a post cap. Posts held on spikes or bolted down to a patio need no buried allowance, so their length simply matches the panel plus any gravel board.

How tall can a garden fence be without planning permission?

In England, a fence can usually be up to 2 m high without planning permission, or 1 m next to a highway used by vehicles or its footpath. The Planning Portal measures both limits from ground level. A 1.83 m panel on a 150 mm gravel board stands 1.98 m tall and sits within the 2 m limit, but the same panel on a 300 mm board reaches 2.13 m and would exceed it. Post caps and trellis count towards the total height.

Different rules can apply to listed buildings, conservation areas and properties where permitted development rights have been removed, and Wales, Scotland and Northern Ireland have their own planning systems. Check with your local planning authority if you are unsure.

How do you measure a fence on a slope?

Measure the horizontal length, then divide the total drop by the number of bays to find how far each panel steps down. Panels are fitted level and stepped, not tilted. On a 15 m run with eight bays and a 0.8 m fall, each panel steps down 100 mm. Gravel boards fill the triangular gaps under each step, and each post must be long enough for the higher of the two panels it carries, so add the step height to the normal post length.

Common mistakes to avoid

Forgetting the posts in the run. Dividing 15 m by 1.83 m gives 8.2 panels, but posts take up space too. Always use panel width plus post width.
Measuring along a slope. The ground distance is longer than the horizontal run, so you may order a panel too many.
Ignoring the gravel board in the height. It adds to both the post length and the overall fence height.
Assuming every “6 ft” panel is identical. Check the actual width in millimetres, especially when mixing panels from different suppliers.
Not checking fixings. Panel clips and screws must suit the post thickness; our screw size guide explains how screw lengths and diameters are described.

Frequently asked questions

How wide is a 6ft fence panel in metres?

A 6 ft fence panel is about 1.83 m wide. Exactly 6 ft is 1.8288 m, and actual panel sizes vary by a few millimetres between manufacturers.

How many fence panels do I need for 10 metres?

With 1.83 m panels and 100 mm posts, five full panels and six posts cover 9.75 m. The last 25 cm needs a narrow cut panel and a seventh post, or a small change to where the fence ends.

How deep should a fence post be?

Around 600 mm is the usual recommendation for posts set in concrete or post mix, which is roughly a quarter of a typical 2.4 m post. Soft or exposed ground may need deeper holes.

What length post do I need for a 6ft fence panel?

With a 150 mm gravel board and 600 mm in the ground you need at least 2.58 m, so buy 2.7 m posts. Without a gravel board the minimum is 2.43 m.

Can I put a 6ft fence on a gravel board without planning permission?

In England, a 1.83 m panel on a 150 mm gravel board is 1.98 m high, within the usual 2 m limit. A 300 mm gravel board would take it over 2 m, so planning permission would normally be needed.

Sources

Fences, gates and garden walls: planning permission, Planning Portal
How deep to dig fence posts, Jacksons Fencing
What size fence posts do I need?, Birkdale Sales