Decking cost calculator
Estimate a new deck in seconds. Enter the size and material to get a realistic supply and install price range for Australia.
Length times width. A typical deck is 15 to 30 m².
Raised decks need more substructure, so they cost more.
- Per square metre$300 to $450
- Deck size20 m²
What a new deck costs in Australia
Most decks land between $200 and $600 per square metre supplied and installed, and the material you pick is the biggest lever. Treated pine is the cheapest way to get a solid deck, hardwoods like merbau and spotted gum cost more but last longer and look the part, and composite costs the most up front but needs almost no maintenance.
Height matters too. A deck sitting just off the ground is quick to frame, while a raised or second storey deck needs more posts, bearers and often a balustrade, which pushes the price up.
| Material | Typical range per m² | Good to know |
|---|---|---|
| Treated pine | $200 to $320 | Budget friendly, needs oiling |
| Merbau or hardwood | $300 to $460 | Popular, hard wearing |
| Spotted gum | $330 to $520 | Premium Australian timber |
| Composite | $350 to $600 | Low maintenance, higher up front |
On top of the deck itself, budget for a balustrade if the deck is more than a metre off the ground, plus stairs, and any permit your council requires for raised structures. Our permit checker covers when approval is usually needed.
Handy gear for this job
If you are oiling or maintaining a timber deck yourself, these are the basics worth having.
- Decking oil for hardwoodView on Amazon AU →
- Deck cleaning brushView on Amazon AU →
- Cordless impact driverView on Amazon AU →
These are Amazon Australia links. If you buy through them we may earn a small commission at no extra cost to you. It never changes the prices we publish.
Common questions
How much does a 20m2 deck cost?
As a rough guide a 20 m² deck runs from about $4,000 in treated pine up to $12,000 in composite, supplied and installed. The calculator above gives a tighter range for your material and height.
Is composite decking worth it?
Composite costs more up front but you skip the sanding and oiling that timber needs every year or two. Over ten years the running cost often evens out, so it comes down to whether you prefer the look of real timber or the low upkeep of composite.
Do I need council approval for a deck?
Low decks under a set height are often exempt, but raised decks usually need approval. It varies by state and council, so check the permit checker and confirm with your local council before you start.
These figures are estimates to help you plan and sense check quotes. They are not a quote. Site access, materials, finish and your location all move the final price. Always get two or three written quotes.
Know a fair price before you call
Browse the rest of the free calculators and hiring guides, or read the cost guides on the blog.