Granny flat site planner — will a 30 m² or 60 m² second dwelling fit on your block, and where?
Search any Victorian or Queensland address, or click a lot on the map above. The planner reads your real parcel from the state cadastre, subtracts the setbacks and easement clearances the state applies, measures the side corridor a builder needs to reach the backyard, and places a 30 m² and a 60 m² unit on the largest compliant footprint it can find. Then it hands you the unit: drag it, rotate it, and watch it stop at the line. It is free, needs no login, and tells you no when the answer is no.
What the planner answers
Most people asking “can I build a granny flat” are really asking three questions at once: is it allowed here, does it physically fit, and can a builder actually get to the spot where it fits. The first is a planning question, the second is geometry, and the third is the one that quietly kills projects after money has been spent on drawings. This planner answers the second and third directly from mapped data, and screens the first against the current state rules — the Victorian planning maps for zone and overlays, and the Queensland state hazard layers plus your council’s secondary dwelling numbers.
The access corridor is the part no other free tool measures. The planner traces the clear gap between your existing house (or garage, carport or shed) and each side fence, and reports both its narrowest pinch point and its widest point — because a corridor that is 4 m wide for most of its length and 0.8 m at one point is a 0.8 m corridor. Below about 1 m nothing gets through. Between 1 and 3 m materials are hand-carried, which adds labour to every stage. At 3 m or more, machinery and prefabricated modules can reach the backyard — the difference between a four-week build and a longer one.
A unit that only fits by sitting on an easement is never scored as a pass. It renders red-dashed and downgrades the verdict, because building over a sewer or drainage easement requires build-over consent from the water authority and is routinely refused for habitable rooms. That single rule is the most common reason a backyard that “looks big enough” is not.
The setback rules the unit obeys — Victoria vs Queensland
Victoria. A small second dwelling of 60 m² or less needs no planning permit on most residential lots over 300 m² (Amendment VC253, gazetted 14 December 2023; Clause 73.03). Siting comes from the Building Regulations 2018: regulation 79 requires at least 1 m from side and rear boundaries for walls up to 3.6 m high, regulation 76 caps site coverage at 60 %, regulation 77 requires 20 % permeability. The National Construction Code requires 1.8 m between the unit and the existing house unless the facing wall is fire-rated — E2ES modules ship with the short end wall fire-rated, so the planner allows 1 m on that face only. Under the Water Act 1989 (s 148) nothing may be built within 1 m of a water authority’s works (5 m laterally of Melbourne Water works) without consent, easement or not — the planner keeps 1 m clear of every mapped easement.
Queensland. A secondary dwelling is defined by the Planning Regulation 2017 (schedule 24), and since 26 September 2022 it may be rented to anyone, not just family. Siting comes from the Queensland Development Code: MP 1.2 (lots of 450 m² and over) requires 1.5 m from side and rear boundaries for walls up to 4.5 m mean height, 6 m to the street, and site cover of 50 % or less; MP 1.1 applies the small-lot variant below 450 m². Maximum floor area is set by each council’s planning scheme, not the state — 80 m² in Brisbane and on the Gold Coast, 70 m² in Logan, a 60 / 90 / 120 m² lot-size ladder in Ipswich, 60 m² on the Sunshine Coast — and the planner reads the lot’s local government area to apply the right cap. Building over or near a sewer follows QDC MP 1.4 and the service provider’s concurrence.
One correction worth making plainly, because the internet repeats it: there is no 550–600 m² minimum lot size for a granny flat in Victoria. The only lot-size number in the planning scheme is 300 m², and below it the answer is “a planning permit is required”, not “prohibited”. In Queensland there is no state-wide minimum lot either — Logan’s 450 m² only selects which siting code applies, and Sunshine Coast’s 600 m² is the one genuine urban minimum among the SEQ councils.
Where the data comes from
Victorian parcels, easements, building footprints, planning zones and overlays and address points come live from Vicmap — the state’s authoritative digital cadastre and planning dataset, published as open data (© State of Victoria, CC BY 4.0). Queensland parcels (including road reserves), easement parcels, the state address database, LiDAR building outlines, locality and council boundaries, and the state acid-sulfate-soils, heritage-register and erosion-prone layers come live from QSpatial (© State of Queensland, CC BY 4.0). Where a footprint layer is empty the planner falls back to OpenStreetMap, and says so.
Everything is computed in your browser from those layers; nothing about your address is stored unless you choose to send it to us with the form. Satellite imagery is display only — every measurement comes from the cadastre vectors, which is how the planner judges distances without pixel-guessing.
What it cannot see
This is a geometric and regulatory screen, not a feasibility report, and the gap between the two is where money is lost. The planner cannot see a title covenant or a Section 173 agreement restricting a second dwelling, an unregistered easement, a sewer main whose real position differs from the mapped alignment, the ground’s bearing capacity, a tree protected under a local law, a structure built without a permit, Queensland council overlays (flood, bushfire, character) that are not published as open data, or what your building surveyor or certifier will require on the day. A green verdict means the block is worth investigating properly. It does not mean you can build, and nothing on this page is planning or building advice.
Frequently asked questions
How close to the fence can I build a granny flat in Victoria?+
Under Building Regulations 2018 regulation 79, a small second dwelling with walls up to 3.6 m high must be set back at least 1 m from side and rear boundaries. The planner applies that 1 m to every fence line and also keeps 1 m clear of any sewer or drainage easement, which water authorities require for access.
How close to the boundary can I build a granny flat in Queensland?+
Under Queensland Development Code MP 1.2, a single-storey secondary dwelling with walls up to 4.5 m mean height must generally sit at least 1.5 m from side and rear boundaries — half a metre more than Victoria. The planner applies 1.5 m to every Queensland fence line plus 1 m clear of sewer and drainage easements (QDC MP 1.4).
Can I build a granny flat over an easement?+
Generally no. Building over a sewer or drainage easement needs build-over consent from the water authority and council, and is usually refused for habitable structures. The planner places units clear of easements automatically; if a unit only fits on top of one, the tool flags it in red instead of approving the site.
Why does the unit stop when I drag it?+
Once your unit reaches a compliant position, the drag is constrained to the compliant zone: it cannot cross the boundary setback, the easement clearance or an existing building. Each edge shows its actual clearance against the required one. If you start in an invalid spot the unit stays movable so you can drag it into the green zone.
Does my driveway width matter?+
Legally no, practically yes. The planner measures the side corridor between the house and the fence from cadastre and footprint data and reports its narrowest and widest points. Under about 1 m nothing gets through; 1–3 m means hand-carried materials; 3 m or more lets machinery and prefabricated modules reach the backyard.
Is there a minimum block size for a granny flat?+
Victoria: the only figure in the planning scheme is 300 m², and below it a planning permit is required rather than the build being prohibited. Queensland: no state-wide minimum; a few councils set one (Sunshine Coast 600 m² in urban zones), while Logan’s 450 m² merely selects which siting code applies. The 550–600 m² figure repeated online is a commercial rule of thumb, not law.
Does the planner cover New South Wales?+
Not yet. It covers every Victorian and Queensland lot with a mapped cadastre. Sydney granny flats run under the NSW Housing SEPP 2021; see our NSW rules guide, and we assess NSW addresses by hand.
Is a green verdict an approval?+
No. Green means a unit fits clear of boundaries, easements and buildings with a usable access corridor, and nothing in the state maps we can read blocks it. It is not planning advice, a permit or an approval. Confirmation happens at the free site assessment and, before construction, through a building permit (VIC) or building approval (QLD).
Read next — the rules behind the planner
Victoria: the VC253 small second dwelling guide
Every condition of the no-planning-permit pathway and what still needs a building permit.
Easements & covenants
Build-over consent, restrictive covenants and Section 173 agreements — the title-level checks the map cannot read.
Queensland secondary dwelling rules
The 2022 rent-to-anyone reform, approvals, council size caps and tenancy law.
Instant address check (VIC)
Zone, overlays and lot size in 30 seconds — the planning-maps screen this planner builds on.