Free. Addresses are looked up with NSW Government planning services; nothing is stored by Plynth. Worked example
Enter a site area, then a permitted ratio, a gross floor area, or both. The result and its working appear here as you type.
Each step names the rule it follows so the table can sit in a file note or Statement of Environmental Effects.
The step table appears once there is a result.
Arithmetic only. Confirm the mapped ratio, site area and each gross floor area classification against the applicable LEP.
Arithmetic on your figures only. The address lookup reads the mapped ratio and lot areas from NSW Government planning data as a starting point; it does not confirm a site area or classify a room, and a council LEP, incentive clause or SEPP can change the standard, so check the LEP and DCP that apply to the land. Meeting the ratio does not establish permissibility or compliance with height, setback, heritage, flood or other controls. Your figures stay in your browser; an address search goes to NSW planning services and is not stored; the share link carries your figures in its address only.
Floor space ratio (FSR) is the gross floor area of all buildings on a site divided by the site area. It is the NSW development standard that caps how much floor space a site can hold: a ratio of 0.5:1 allows 0.5 m² of gross floor area for every square metre of site, so a 600 m² site allows 300 m². Outside NSW the same control is usually called floor area ratio or plot ratio.
The ratio counts floor area, not footprint, so height, setbacks and site coverage are separate controls. Clause 4.4 of the Standard Instrument LEP ties the maximum to the Floor Space Ratio Map and clause 4.5 defines the ratio and the site area; each council LEP adopts those clauses with its own map and local modifications.
floor space ratio = gross floor area ÷ site area
Find the Floor Space Ratio Map value for the land in the applicable LEP, then read clause 4.4 and any local clause that adjusts it.
Take the lot, or the contiguous lots the development sits on, and remove the land that clause 4.5(4) excludes.
Measure every floor of every existing and proposed building at 1.4 m above the floor and apply the Dictionary's inclusions and exclusions.
Gross floor area ÷ site area is the ratio achieved. Site area × permitted ratio is the maximum, and the difference is the floor area remaining or over.
Follow the worked example for a step-by-step calculation on assumed figures.
Measured from the internal face of the external walls, or the walls shared with another building, at 1.4 m above the floor.
Floor space ratio is the ratio of the gross floor area of all buildings within a site to the site area. It is the NSW planning control that limits how much floor space a site can hold, expressed as a figure such as 0.5:1 or 2:1. The same idea is called floor area ratio or plot ratio in other jurisdictions.
Divide the gross floor area of all buildings within the site by the site area. A 300 m² gross floor area on a 600 m² site is a floor space ratio of 0.5:1. Clause 4.5(2) of the Standard Instrument LEP sets that definition, and the site area and gross floor area each have their own rules.
Search the address in this calculator: it reads the mapped ratio for the property from the NSW Planning Portal's Floor Space Ratio layer, names the LEP and clause, and fills the ratio for you to confirm. Otherwise read the Floor Space Ratio Map in the LEP that applies to the land through the NSW Planning Portal Spatial Viewer. Either way, read the written clause 4.4 and any local clause that adjusts the map. Some sites carry more than one ratio, and some LEPs set the maximum by a formula, a schedule or an incentive provision rather than the map alone.
Car parking that meets the consent authority's requirements, including access to it, is excluded under paragraph (g) of the definition, and basement vehicular access, loading, garbage and services areas are excluded under paragraph (e). Parking above the required number of spaces is not excluded by those paragraphs, so check the DCP rate before you exclude it.
Terraces and balconies with outer walls less than 1.4 m high are excluded under paragraph (i). An enclosed balcony or a terrace with a taller wall is measured like any other floor area.
Yes. Clause 4.5(8) includes the gross floor area of any existing or proposed building within the vertical projection of the site boundaries, even when the proposal does not change every building. Add retained buildings to the schedule.
The calculator reports the excess in square metres and as a share of the control. Clause 4.6 lets a consent authority grant consent to development that contravenes a development standard such as FSR when it is satisfied the applicant has demonstrated the matters in clause 4.6(3), unless the standard is excluded from that clause. That written request is a planning judgement this tool does not make.
No. It does the arithmetic on figures you enter and shows the rules behind each step. The address lookup reads the mapped ratio and lot areas from NSW Government planning data as a starting point; it does not confirm a site area, classify a room, or apply council-specific variations, incentives or SEPP provisions. Check the applicable LEP and DCP, and use survey drawings for a real site.
From NSW Government services. The NSW Planning Portal's address search finds the property, its planning-layer query returns the mapped floor space ratio, zone and height of buildings, and the NSW cadastre supplies the registered lot areas. Plynth's server passes each request on and caches the answer for about a day; the address is not stored or logged, and nothing about your design is sent. Contains NSW Government data, CC BY 4.0.
Standard Instrument (Local Environmental Plans) Order 2006, current version for 1 July 2026 to date. Read on the NSW legislation website on 25 September 2026. Council LEPs adopt these clauses with their own map and local modifications.
Contains NSW Government data from the NSW Planning Portal and NSW Spatial Services, CC BY 4.0. Plynth's server relays each lookup and caches the answer for about a day; addresses are not stored or logged.
Plynth answers site questions like this with every control linked to its source: the mapped ratio, the written clause, the zoning and the other standards that apply to the same parcel.