What does your block actually allow?

Common questions

R-Code questions, answered

What is an R-Code?

Your Residential Design Code, the 'R' number on your block (like R20 or R40), is the state's density rule. It sets how many dwellings the land can carry and the standards they have to meet, such as minimum and average site area per dwelling. A higher number generally means more density is possible, but the code is only the starting point. The block's shape, size, frontage and constraints decide what actually gets approved.

Does a higher R-Code always mean I can subdivide?

No, and this is where a lot of owners get caught out. The R-Code sets the ceiling, but your block still has to have enough area, the right frontage and a workable layout to reach it. A block can carry a generous code and still only yield one dwelling because the numbers or the site do not stack up. That is exactly what this tool checks for you before you spend anything.

How does the tool know what my block allows?

When you enter your address it reads the official planning data for that specific lot: the coding, the zone, the lot area and the constraints that sit over it. It then applies the current Residential Design Codes to work out the indicative yield, the pathway that makes the most of the block, and an indicative cost band. Every figure it shows is sourced from the code or the official data, or it is not shown at all.

Is this planning advice I can rely on?

It is an honest indicative read, not formal planning or financial advice, and not a decision from your council. Local planning policies vary between councils and can change the outcome, and some things such as sewer, easements and the finer detail still need to be confirmed properly. Treat the result as a fast, sourced starting point that tells you whether your block is worth taking further, then verify the detail before you commit.

What is the 2027 R-Codes reform, and does it affect me?

In July 2026 the state announced a proposal to change how density is worked out for lower-density blocks, including removing the average site area rule for R20 and below. It has been announced, not made law, so nothing has changed yet. But it could change whether thousands of Perth blocks become subdividable. The tool flags where the reform is relevant to your block, and the reform explainers on the site walk through what was announced and how to weigh it.

Why does it ask for slope and soil?

Because both move the cost, and leaving them out would give you a prettier number than reality. Slope affects retaining, drainage and site works. Soil class affects footings. Asking for them up front means the indicative cost band reflects your actual block rather than a flat, easy site. If you are not sure, the tool takes a sensible default and tells you to confirm it.

Is it really free, and what is the catch?

It is free to use and free to see your result, with no sign-up to get the answer. There is no catch. We build these tools because the owners who find them useful are often the ones who later want a proper feasibility done, and that is our work. You are under no obligation to take it further.

My block is dual-coded (for example R20/R40). What does that mean?

Dual coding means the block sits under two densities, with the higher one available if certain conditions are met. The tool assesses the block at the higher code so you can see the upside, and shows the base entitlement alongside it so you know the floor. Whether the higher code is achievable depends on the conditions attached to it, which a feasibility confirms.