Building Height Limit Calculator
How many storeys fit under a height limit — or how tall a given number of storeys will be — from the floor-to-floor heights that ground floors, upper floors and roof plant actually take.
A height limit in metres does not translate to storeys by simple division, because the ground floor is usually taller, and plant and parapets sit on top.
How the building height limit calculator works
A height limit in metres does not translate to storeys by simple division, because the ground floor is usually taller, and plant and parapets sit on top. This models each part separately.
The practical result is that a 30-metre limit gives eight residential storeys, not ten — and knowing that before the sketch is what this is for.
Formula: height = ground + (storeys − 1) × typical + roof; storeys = 1 + (limit − ground − roof) / typical
Worked examples
| Inputs | Storeys that fit | Note |
|---|---|---|
| A 30 m limit | 8 | eight storeys, not ten |
| A 45 m limit | 12 | thirteen storeys |
| Tighter floors | 9 | one more storey |
FAQFrequently asked questions
How many storeys is 30 metres?
Eight for typical residential — a 4.5 m ground floor, 3.2 m upper floors and 2.5 m of plant. Dividing 30 by 3 and getting ten is the usual mistake.
What is floor-to-floor height?
Slab to slab, including the structure and services. It is about 0.4 to 0.6 m more than the ceiling height you stand in.
Why is the ground floor taller?
Retail, lobbies and services need it. Four to five metres is standard; a purely residential ground floor can be closer to the typical floor.
Does roof plant count toward the limit?
Usually, though many schemes exempt lifts overruns and plant within a set area. Check the definition of height in your scheme.
Is the limit to the parapet or the roof?
Depends on the scheme — some measure to the highest point, some to the ceiling of the top storey. The plant allowance here covers the difference.
Where these figures come from
- UN-Habitat — Urban Indicators Guidelines — density, green space and public space benchmarks
- World Health Organization — Urban green spaces — the 9 m² per person minimum
- ITE — Parking Generation Manual — parking demand rates by land use
- Australian Bureau of Statistics — Regional population — Australia's national statistics agency
Last checked: September 2026. Default per-capita rates are mid-range figures from national statistical agencies and utility reports; every one is an input you should replace with the local figure.