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Decking calculator for a UK deck, frame included
Store calculators tell you how many boards to put in the trolley. This one works out the whole deck: boards, joists, beams, posts, footings, steps, railing and fixings, in UK buying lengths, drawn in 3D while you type. Free, no sign-up, and nothing is priced until you add your own rates.
BuildPlot3D is independent and not affiliated with B&Q, Wickes or any retailer.
Example numbers, until you enter your size
- Decking boards
- 50 at 3.6 m
- Joists
- 14 at 400 mm centres
- Posts and footings
- 16 and 16
- Deck area
- 17.8 sq m
Rows packed into UK stock lengths, 5% waste included
Spacing from UK timber decking practice (BS 8579)
Posts at most 1.8 m apart
Finished deck, measured to the outside of the frame
The full list has beams, footings, steps, railing, fixings and the cut list.
Open the designer to change the material, the height, the railing and the steps, then inspect the full take-off, then get the order-ready PDF and CSV in the complete pack.
Inspect the full listWhat a store calculator covers, and what it does not
| Part of the job | Typical store calculator | Here |
|---|---|---|
| Decking boards | Yes, from their own range | Yes, any board width and gap |
| Joists and beams | Sometimes, fixed spacing | Yes, spacing follows the material |
| Posts, footings, concrete | No | Yes, with spacing rule shown |
| Screws, clips, hangers | No | Yes, counted from the frame |
| Steps and railing | No | Yes, risers worked out from the height |
| Cut list and offcuts | No | Yes, packed into buying lengths |
| 3D view of the deck | No | Yes, while you type |
| Price | Their stock prices | Your own rates, or nothing |
Nothing wrong with buying the boards at a shed. The gap is that the frame, the footings and the fixings are most of the timber and nearly all of the mistakes, and they are the part a shop calculator is not trying to answer.
Common questions
Is this the B&Q decking calculator?
No. BuildPlot3D is an independent tool and is not connected to B&Q or any retailer. It is here because people searching for a store calculator usually want a full list of what to buy, not only the boards a single shop stocks.
What does a retailer calculator leave out?
Most give you board count and sometimes joists, priced from their own range. The frame under the deck is what costs the money: beams, posts, footings, concrete, joist hangers and hundreds of screws or hidden clips. Those are in this list.
Does it use UK sizes?
Yes. Boards and timber are packed into 3.0 m, 3.6 m, 4.2 m and 4.8 m, joist spacing follows UK timber decking practice, and you can switch to Ireland, the US or Canada if you are building there.
Will it price my deck?
Only with rates you enter yourself. There are no retailer prices here and no national averages, because a price built from someone else's rates is the reason online figures come in under the real quote.
Can I take the list to a merchant?
Yes. Inspect the full list free, then use the Full Build Pack for the order-ready PDF and CSV a yard can price directly.
Is it a structural design?
No. It is a material take-off for planning and pricing. Spans, footings and railings still need checking against local rules and, where needed, building control.
Free, no account. Nothing is priced until you add your own rates. See a sample pack
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