Calculators

Match the job to the tool:

• Building a deck — Deck Estimator Pro. It covers the frame and the decking together.
• Privacy screen, batten wall or screen fence — Screening Estimator Pro.
• Balustrade on a deck (the posts and handrail around the edge) — Structural Estimator Pro.
• Timber cladding or wall lining — Cladding Estimator Pro.
• Oiling or re-oiling a deck, screen or cladding — Coating Estimator Pro.

If your job has more than one of these in it, that is normal — see the question on using them together below.

Deck Estimator Pro, and start there before anything else.

It is the most complete of the five. It works out the framing and the decking together, and it can add extras onto the same job — balustrade, privacy screen, cladding and oil — so you end up with one order rather than five separate guesses.

It also prices everything in real, in-stock products you can put straight into your cart.

No. The other four stand on their own.

If you are replacing a screen, cladding one wall, adding a balustrade to an existing deck, or just buying oil, go straight to that calculator. The deck calculator is for when the frame and the boards are part of the job.

It asks plain questions about your deck and works out what to order — framing, decking, and any extras such as a balustrade, privacy screen, cladding or oil.

The first thing it asks is what your frame is made from: treated pine (MGP10 H3), which is the most affordable option, or solid Merbau hardwood (F27), which people choose for the look and longevity.

Everything it returns is a real, in-stock product with a real price, ready to add to your cart. No trade knowledge needed — it explains each term as it goes.

It works out the battens, lineal metres and fixings for a timber screen or privacy fence panel.

You give it the screen width and height, whether the battens run vertical or horizontal, your batten width, and the batten length you are buying. There are advanced options for the gap between battens and for support rails.

Batten widths run from 19mm up to 90mm, and lengths from 1.8m to 4.8m.

It works out the posts and handrail lineal metres for a deck balustrade — the railing around the open edges of a deck.

You give it the balustrade length, the post height above the deck, your post spacing and how many handrail runs you want (top rail, mid rail and so on).

It is a materials calculator. It works out quantities from the numbers you enter — it does not decide your post spacing, height or sizing. More on that below.

It works out the lineal metres for hardwood chamfer, weatherboard-style or tongue-and-groove cladding.

You give it the wall length and height and the board profile. There are advanced options for waste allowance and batten spacing.

The important part is that it calculates on the board's cover width, not its overall width — which is the thing most people get wrong when estimating cladding by hand.

It works out how many litres of WOCA Exterior Wood Oil you need for a deck, cladding or screen.

You give it the area in square metres, the number of coats (1, 2 or 3), and your WOCA colour. There are advanced options for the coverage rate and waste.

Two coats — a first coat plus a recoat — is the usual choice on bare timber.

Work in the order you would build:

1. Deck Estimator Pro first, for the frame and the boards.
2. Structural Estimator Pro for the balustrade around the finished deck.
3. Screening Estimator Pro for any privacy screen going in alongside it.
4. Cladding Estimator Pro if you are cladding a wall or the deck surround.
5. Coating Estimator Pro last, once you know the total area you are coating.

The deck calculator can also pick up several of these as extras within the one job, which saves doing them separately.

Run the Deck Estimator Pro or Screening Estimator Pro first — they give you the area, and you carry that number into the coating calculator.

Remember to add up everything you are coating, not just the deck. A deck plus a privacy screen plus a handrail is a much bigger area than the deck alone, and running out of oil part-way through a job is how you end up with a visible join.

Deck Estimator Pro returns real, in-stock products at real prices that go straight into your cart.

The other four give you quantities to work from. Send us the results and we will turn them into an order, check the fixings, and tell you what is on the shelf.

• Deck — length and width of the deck, and how high it sits off the ground.
• Screen — the width and height of the screen, in millimetres.
• Balustrade — the length of the open edges only, and your confirmed post height above the deck.
• Cladding — wall length and height, and the cover width of your board.
• Coating — the total area in square metres, and how many coats.

Measure the real thing rather than working from a plan where you can. Most of the inputs are in millimetres.

Only the open edges that need a balustrade — usually not the side against the house.

Measuring the full perimeter is the most common mistake here, and it will have you ordering posts and handrail you do not need.

Cover width is the face each board actually hides on the wall once the boards are overlapped or tongue-and-grooved together. It is always narrower than the board's overall width.

Estimating cladding on the overall width is why people run short. Our 134×19mm hardwood chamfer board, for example, has a 122mm cover — so every board hides 122mm of wall, not 134mm.

If you are using a different profile, enter its cover width. It will be on the product page, or ask us.

Because it changes how many you need and how much you waste.

A screen 2.4m high built from 2.4m battens has almost no offcut. The same screen built from 3.0m battens leaves 600mm off every single one. Choosing the length that divides best into your screen height is the easiest saving on the whole job.

It adds a percentage on top of the calculated quantity to cover offcuts, cuts around obstacles and the occasional bad board.

Every calculator with advanced options lets you set it. Increase it for a deck with lots of angles, cuts or a herringbone pattern; the default is fine for a straightforward rectangle.

They are a solid guide, not a quote. They work from the numbers you enter, so the results are only as accurate as your measurements.

Send us the results before you order and we will check them against what is actually on the shelf, confirm the fixings, and flag anything that looks off.

Partly, and it is important to know where the line is.

For pine framing, Deck Estimator Pro checks your sizes against a verified engineering table automatically, so you will know straight away whether a size is safe for your deck.

For hardwood F27 framing, the sizing is a starting point only. Confirm it with an engineer or your local council.

For a balustrade, the calculator does not determine your post spacing, height or sizing at all — it only calculates quantities from the numbers you give it.

These are safety-critical and set by the National Construction Code and the Queensland Development Code. They vary by post size and timber grade.

Published guidance for timber newel and full-height posts ranges from around 1.3m up to 3.6m centres depending on grade and post size — there is no single safe default.

Confirm your exact spacing and height with a certified builder or your local council before you order or build. Enter the confirmed figure into the calculator, not a guess.

Talk to us. Curved decks, multi-level decks, commercial work, unusual profiles and anything structurally out of the ordinary are all worth a conversation rather than a calculator.

Send through your dimensions, what you are building and the timber you have in mind, and we will work the materials out with you.

Browse the full Decking Wood QLD range of decking, structural timber, screening, cladding, hardware and coatings.