Decking Calculator — Estimate Your Composite Decking Materials

4000 × 148 × 21mm boards
10% wastage included automatically

Britwall Decking Calculator

Use this calculator to estimate exactly how many decking boards, edging trims and fixing clips you need for your project. Enter your deck dimensions, choose your board colour and we'll work out the materials — including a 10% allowance for cuts and wastage — and add everything straight to your cart.

How to use this calculator
  1. Select your deck shape — choose the layout that best matches your garden space.
  2. Enter your dimensions — measure in metres. We add 10% wastage automatically.
  3. Choose your board & edging colour — all boards are 4000 × 148 × 21mm at £41.45/m².
  4. Adjust clip quantities — we suggest quantities based on your area; adjust if needed.
  5. Add to cart — everything goes into your basket in one click.

Not sure what you need? Our team is happy to help — get in touch and we'll guide you through it.

+44 020 4579 3704 enquiries@britwall.com
1

Select a shape

2

Enter dimensions

Enter the full diameter of your circular deck.
A semicircular deck — enter the diameter of the full circle.
Two rectangles joined at a corner — enter each section separately.
Mirrored L — sections join at the opposite corner.
Outer rectangle size minus the open centre cutout.
Main rectangle plus a hook extension at the base on one side.
Total deck area: 20.0 m²

Measure in metres. 10% wastage is automatically added to board quantities.

3

Choose your decking board

SELECTED
Teak B decking board
Teak B 3D Embossed
4000 × 148 × 21mm
£41.45/m²£31.50/board
SELECTED
Dark Coffee decking board
Dark Coffee 3D Embossed
4000 × 148 × 21mm
£41.45/m²£31.50/board
SELECTED
Light Grey decking board
Light Grey 3D Embossed
4000 × 148 × 21mm
£41.45/m²£31.50/board
View all decking boards →
4

Edging trim

Premium composite edging trim — 45 × 45 × 2400mm. Gives your deck a clean, professional finish.

Select edging trim colour:

SELECTED
Teak edging trim
Teak
£10.00 / 2.4m
SELECTED
Dark edging trim
Dark
£10.00 / 2.4m
SELECTED
Light Grey edging trim
Light grey
£10.00 / 2.4m
5

Fixing accessories

Quantities are auto-calculated from your deck area. Adjust using the +/− buttons if needed.

Stainless steel mid-run clips
Stainless Steel Clips
Mid-run board fixings
£2.00 each
Suggested: —
Stainless steel starter clips
Stainless Steel Starter Clips
First row fixings
£2.00 each
Suggested: —

Your materials estimate

All prices inc. VAT
Total deck area20.0 m²
Decking boards (inc. 10% wastage)—
Board selectedTeak B 3D Embossed
Edging trim (2.4m lengths)—
Mid-run stainless clips—
Starter clips (first row)—
Decking boards cost—
Edging trim cost—
Fixing clips cost—
Estimated total
All prices inc. VAT
£—

Quantities based on your dimensions. Adjust in the cart before checkout if needed.