Whether you search for a deck calculator or a decking calculator, you are after the same thing: a tool that works out the material requirements for your deck. There are, however, several types of calculators for different needs – some estimate deck boards and screws, others framing, price, or the entire structure. Here is a quick overview of what you actually need.
Which calculator fits your project?
| Project | What you need to estimate |
|---|---|
| Low ground-level platform | Deck boards, screws, simple framing |
| Standard deck by the house | Deck boards, screws, joists, footing points |
| Raised deck/veranda | All of the above, plus beams, railings, and stairs |
| Replacing boards on an existing deck | Deck boards and screws only |
- Building a ground-level platform? The need is simplest: the boards sit low, and what matters most is the right quantity of boards and screws. See how to use a deck platform calculator.
- Building a standard deck? You also need to plan the joists – the standard is 60 cm (24 in) on center, or 40 cm (16 in) for thin boards, diagonal layouts, or composite. Read what joist spacing should you use?
- Building a raised deck or veranda? Beams, railings, and stairs come on top – there you should calculate by hand or with a professional, not just with a calculator.
What our calculator estimates
The calculator on this page is a materials calculator for the decking surface. You enter the deck’s dimensions and board width, and get:
- Linear length of deck boards – based on about 8.3 linear meters per m² with 120 mm (4 3/4 in) boards (roughly 2.5 linear feet per sq ft), adjusted for the board width you choose
- Number of screws – based on the rule of thumb of 35–40 screws per m² (3–4 per sq ft, two screws per board per joist)
- A built-in buffer for waste, so you do not order right at the limit
If you want to understand the numbers behind it, deck boards per square meter shows the conversion from area to linear length, and estimate deck screws for your project explains the screw calculation.
What it does not do
To avoid misunderstandings: the calculator does not estimate
- dimensions and quantities for joists, beams, and footings
- price – it varies too much between suppliers and material types
- railings, stairs, or roof structures
- whether your project needs a permit (you have to check that yourself – see can you build a deck without a permit?)
In other words, it gives you a precise shopping list for the deck surface itself, while the structure underneath must be planned from span tables and manufacturer guidance.
Get the first order right
Many people buy too little and have to go back to the lumber yard mid-project – or too much, which ends up sitting unused. With a realistic estimate plus about 10 % waste allowance, you usually get it right on the first try. Start with the calculator, and use the step-by-step deck building guide when it is time to build.