Deck Cost Calculator
The boards are the easy part — it's the frame, steps and rails that move the price.
Estimate the cost to build a deck: per square metre by material — treated pine, merbau, spotted gum or composite — supplied-and-installed or as DIY materials only, with add-ons for steps, a balustrade and an elevated frame, plus a low-to-high range because deck pricing genuinely varies from one site to the next.
Estimates from your deck size and typical AU rates — deck pricing varies a lot, so confirm scope and price with itemised quotes.
How the deck cost is worked out
Area × $/m² by material and basis, then the extras
The calculator takes your deck's area (length × width) and multiplies it by a per-square-metre rate for the material and basis you pick — supplied-and-installed or DIY materials only — at a low, typical or high price band. It then applies an elevation multiplier if the deck is over about a metre off the ground, adds any steps and balustrade, and finishes with a contingency buffer. Because deck pricing genuinely varies with the site, frame and finish, it also shows a low-to-high range rather than pretending there's one exact number.
Worked example
A 20 m² merbau deck at ground level, supplied and installed at the typical rate of about $400/m², is roughly $8,000 for the deck surface. Add a 10% contingency and you're near $8,800 — before any steps, a balustrade or an elevated frame. Swap to treated pine (~$250/m²) and the same deck is about $5,000; step up to premium composite (~$650/m²) and it's about $13,000.
Decking materials and what they cost
Typical supplied-and-installed rates by material (2026 market-survey ranges — approximate):
- Treated pine — ~$250/m² (about $180–$350). Cheapest to build; needs oiling or staining every year or two.
- Merbau / hardwood — ~$400/m² (about $300–$550). The popular middle ground — rich colour, hard-wearing, still needs oiling.
- Spotted gum — ~$470/m² (about $350–$600). A premium Australian hardwood with a dense, tight grain.
- Composite, mid-range — ~$420/m² (about $280–$550). Capped, hollow-core boards; no oiling, just a wash.
- Composite, premium — ~$650/m² (about $500–$900). Solid-core, best look and feel; dearest to build, near-zero upkeep.
The trade-off is price vs upkeep vs looks. Treated pine wins on upfront price but costs the most to maintain. Hardwoods like merbau and spotted gum look the best and wear well, but need oiling to hold their colour. Composite costs the most to build yet never needs oiling — you're paying upfront to buy back a decade of weekends. There's no single "best" board; it depends on your budget, how long you'll keep the deck, and how much maintenance you're willing to do.
DIY, elevation, steps and getting a real quote
Building it yourself
Labour is roughly half a deck's installed price, so DIY materials only cost about half the installed figure. On a 20 m² treated-pine deck that's around $5,000 installed versus about $1,600 in materials — a saving near $3,400. Real money, but a deck needs footings, a level frame, correct bearer and joist spans and often a council permit, so budget your time and skill honestly and check what's allowed before you start.
Elevation, steps and balustrade
A deck more than about a metre off the ground costs roughly 30–50% more — taller posts, deeper footings, bracing, a balustrade by law and sometimes engineering. Steps run about $150–$400 each, and a balustrade is roughly $120–$350 per metre (timber-and-wire around $180/m, glass around $320/m). These add up fast, so set them at the Detailed precision level for a realistic total.
Getting an accurate quote
This tool is a planning ballpark. For a real number, get at least three itemised quotes for the same scope (size, material, steps, balustrade, height), and check each one includes footings, the subframe, fixings, waste removal and any permit, and whether it's supplied-and-installed or labour-only. A big spread between quotes usually means the builders have priced different scopes.
❓ Frequently asked Frequently asked questions
How much does a deck cost in Australia?
As a rough guide, a supplied-and-installed deck runs about $250/m² for treated pine, $400/m² for merbau, $470/m² for spotted gum, and $420–$650/m² for composite. So a 20 m² deck at ground level is roughly $5,000 in pine or $8,000 in merbau before steps, a balustrade or elevation. These are 2026 market-survey ranges that vary with your site and finish — always get itemised quotes.
What's the cheapest decking material?
Treated pine is the cheapest to build, about $180–$350/m² installed (typically around $250). That's less than half the cost of premium composite, but pine needs oiling or staining every year or two, so it's the dearest to keep looking good. Merbau and other hardwoods sit in the middle on both price and upkeep.
Is composite decking worth the extra cost?
Composite costs more upfront — about $280–$550/m² for mid-range and $500–$900/m² for premium, versus roughly $250/m² for pine — but it never needs oiling or staining, just an occasional wash. Over ten years the maintenance saving can close much of that gap, so it often pays off if you'll keep the deck a long time and don't want the upkeep.
How much can I save building it myself?
Labour is roughly half a deck's installed price, so DIY materials cost about half the installed figure. On a 20 m² treated-pine deck that's around $5,000 installed versus about $1,600 in materials — a saving near $3,400. But a deck needs footings, a level frame, correct bearer and joist spans and often a council permit, so budget your time and check what's allowed before you start.
Why does an elevated deck cost more?
A deck more than about a metre off the ground needs taller posts, deeper footings, bracing, a balustrade by law and sometimes engineering, so it typically costs 30–50% more than the same deck at ground level. This calculator applies an uplift multiplier — about ×1.4 by default — when you set the deck to elevated.
Do these prices include steps and a balustrade?
The per-m² rate covers the deck surface — the boards plus the subframe. Steps and balustrades are separate: budget about $150–$400 per step and $120–$350 per metre of balustrade (timber-and-wire around $180/m, glass around $320/m). Add them at the Detailed precision level for a realistic total.
Where these figures come from
The cost here is built from your deck's size and a per-square-metre rate — there is no single official price for a deck, because it depends heavily on the material, the frame, the site and the finish. The rates below are 2026 market-survey ranges drawn from typical Australian builder and supplier pricing; they are approximate and design-dependent, not a quote.
- Installed rates (typical) — treated pine ~$250/m², merbau ~$400/m², spotted gum ~$470/m², mid composite ~$420/m², premium composite ~$650/m². Each has a wide low-to-high band because sites and finishes vary.
- DIY materials — roughly half the installed rate, since labour is about half the job. You still supply the footings, subframe timber, boards and fixings.
- Add-ons — elevated decks add about 30–50%; steps run $150–$400 each; balustrade $120–$350 per metre depending on style (timber-and-wire vs glass).
- Upkeep — timber decks need oiling or staining every one to two years; composite needs only an occasional wash.
Last checked: July 2026. All prices are indicative market ranges and vary by region, material, site and design. This is a planning estimate — always get at least three itemised quotes for the same scope before you commit.
Select the question that matches where you are right now.
The headline number is the estimated cost of your deck: the deck surface (area × rate for your material and basis) plus any elevation uplift, steps, balustrade and a contingency buffer. The range underneath shows how much that can move as pricing swings from budget to premium.
Use it to set a budget and sanity-check the quotes you get. If a quote lands well outside the range, ask what's different — the material, the frame, the site or the scope.
It's not a fixed quote or a structural design. It doesn't size footings, bearer and joist spans, or bushfire/cyclone requirements — those come from your builder, engineer or council.
Deck pricing genuinely varies. The same deck can differ 30–50% on site conditions, access, height and finish alone, which is why the tool shows a low-to-high band rather than one number.
Four things move a deck's cost the most: the size, the material, whether it's installed or DIY, and the height and add-ons.
The board is the biggest single lever on the rate — pine at ~$250/m² versus premium composite at ~$650/m² is more than double. Pick for how long you'll keep the deck and how much upkeep you'll do.
Labour is about half the installed price. Doing it yourself can nearly halve materials cost, but you take on footings, a level frame and a possible permit.
An elevated frame adds 30–50%; steps are $150–$400 each; a balustrade is $120–$350 per metre. A ground-level deck with no rail is the cheapest build — every metre up and every add-on lifts the total.
A few habits keep the estimate honest and the quotes comparable.
Use the actual deck length and width, and set the height and add-ons at the Detailed level. A deck that looks small on paper grows once you add steps and a rail.
Get three itemised quotes for the same scope and material. Check each includes footings, subframe, fixings, waste removal and any permit before you compare the totals.
A cheap timber build can cost more to own once you count oiling every year or two. Weigh the upfront saving against a decade of upkeep before choosing the board.
A deck is usually one line in a bigger outdoor or renovation budget. Model the rest of the job and the money side too.
Need concrete for footings, a landing or a slab under the deck?
Concrete slab calculator →Check what you could borrow before committing to a bigger build.
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