Trellis toppers sit on top of fence panels or walls to add height and privacy without blocking light — and they give climbing plants something to hold. Enter the length of your fence run and this calculator rounds up to whole 1.83m panels, then prices the trade pack of 6 against single panels.
Diamond trellis is the classic choice and suits most gardens. Because toppers are light, they can usually fix to your existing posts with brackets or battens — no new posts needed unless yours are rotten.
01 — The Calculator
Pick a material, pace out your plot, and the value engine prices every way to fill it — hippo bags, dumpy bags or handy sacks.
Enter dimensions to calculate.
Fence run
0.0 m
Toppers needed
0 × 1.83m
Full packs
0 of 6
Single toppers
0 top-up
Best price
—
Trellis toppers match standard 1.83m panel widths — enter the same run as the fence they sit above.
Enter your plot dimensions and the value engine will price the cheapest way to cover it.
Worked example: topping a 12m fence
A 12m run needs 7 toppers (12 ÷ 1.83m, rounded up) — the cheapest route is one trade pack of 6 plus a single panel, about £81.95 all-in. That is typically £13 less than buying 7 singles, and the calculator shows both.
The 2-metre planning rule still applies — trellis counts towards the total height beside a boundary (1 metre next to a highway). Most 1.8m fences with 300mm trellis toppers sit right at the limit, which is why toppers are sold at 300mm or 450mm.
Garden Calculator — Project
My garden project · 29 September 2026
| Item | Qty | Each | Total |
|---|---|---|---|
| Estimated total | £0.00 | ||
Prices from the Garden Calculator sample trade catalogue — confirm with your merchant before ordering.