Gross Floor Area is URA's measure of development intensity. URA defines it as "All (a) covered floor area of a development, (b) uncovered area used for commercial purposes, and (c) strata area (covered or otherwise) of a development are included as GFA, unless otherwise exempted."
URA adds the measurement rule in the same breath: "GFA is the total area of covered floor space, including the half thickness of external walls or other building facade elements (e.g. windows, railings, curtain walls), but excluding voids." Everything else on this page is a consequence of those two sentences, or an exception URA has written to them. The source is URA's GFA introduction page.
Measured to the middle of the wall, and that changed in 2023
GFA includes the half thickness of external walls, which means the measurement runs to the middle of the wall. Wall finishes are not counted. For a curtain wall, URA states that "The GFA is measured up to the middle of the outermost vertical facade element (e.g. the glass panel)."
This is recent, and it is the most useful date on this page. URA circular DC22-09 states that "All agencies' floor areas will be measured to the middle of the wall", and records that URA's previous definition "is measured to include the full thickness of external walls but excludes voids." The middle-of-wall rule took effect on 1 June 2023 for development applications to URA, and on 1 September 2022 for Government Land Sales and iGLS sites launched for sale.
The consequence is worth stating plainly: a GFA figure computed before June 2023 was computed on a different rule. Anyone comparing an old approval against a fresh computation is comparing two different measures, and may either invent a discrepancy that is really a definitional change, or miss a real one.
On party walls, URA says: "For buildings with party walls, which refer to the shared wall along the common boundary of two separate developments, GFA computation will include the thickness of the party wall that is part of the building." We are quoting rather than paraphrasing because the wording is genuinely ambiguous as to whether "the thickness that is part of the building" means the full or the half thickness, and URA does not resolve it on the page. If a party wall is material to your computation, put the question to URA rather than to a consultant's assumption.
Voids are excluded from GFA. Since DC22-09, all voids are also excluded from strata area.
Four agencies, four floor areas
If four consultants have given you four different floor areas for the same building, this is why. DC22-09 sets out that four agencies measure floor area for four different purposes:
| Agency | Measure | Purpose |
|---|---|---|
| URA | Gross Floor Area (GFA) | Measuring building intensity |
| SLA | Strata area | Demarcating ownership |
| BCA | Statistical Gross Floor Area (SGFA) | Measuring total floor areas |
| SCDF | Accessible Floor Area (AFA) | Determining fire safety requirements |
DC22-09 harmonised them: all measured to the middle of the wall, all strata areas included as GFA, all voids excluded from strata area, and BCA and SCDF adopting an aligned SGFA definition. What it did not do is make them the same number. They still answer different questions.
GFA and Gross Plot Ratio
Gross Plot Ratio is how the Master Plan turns a site into a development right: it relates the floor area a development may build to the area of the site it sits on. URA states that "The allowable Gross Plot Ratio (GPR) of a commercial development is guided by the GPR specified in the Master Plan (MP). The MP plot ratio is the upper bound as it may not always be achievable because of site limitations." Read that carefully: the Master Plan figure is a ceiling, not an entitlement, and site constraints can put it out of reach.
What counts as GFA and what does not
The authoritative source is URA's Handbook on Gross Floor Area, last updated 9 June 2026, which carries a separate subpage for each building element. The tables below summarise those subpages. Read them as a map of where to look, not as a substitute for the handbook item that governs your case.
Counted as GFA
| Item | Rule |
|---|---|
| Balconies | Included as GFA. May draw bonus GFA under the Balcony Incentive Scheme: included, but funded from a bonus budget. |
| Bay windows | "Bay windows, except those approved before 1st January 2009, are included as GFA." Defined as raised windows not exceeding one structural bay width and cantilevered at least 0.5m high from the floor. |
| Void decks | "Void decks are included as GFA." No stated conditions. |
| Walls and columns | "Walls and columns are included as GFA." |
| Covered swimming pool | "Covered swimming pool is included as GFA." The handbook subpage addresses covered pools only. |
| Household shelters | Included. Excluded: the shelter core extending into the foundation, the RC slab at intermediate floor levels, and the RC slab at roof level. |
| Private planter boxes | "Private planter boxes located within strata units of both residential and non-residential developments are included as GFA." |
| Floors under pitched roofs and raised platforms | Counted where the springing-line-to-ridge height is at least 1.5m, or the platform height exceeds 1.5m. Intermediate load-bearing floors are counted. Covered perforated floors are counted "regardless of the type of material used." |
| Non-car-park uses on car park floors | Staircases, storage, toilets and non-parking corridors are counted. |
| Courtyards and air wells within strata areas | Counted "whether they are open or covered". |
Partially counted
| Item | Rule |
|---|---|
| Lift shafts | "Lift shafts, including the half thickness of the walls, are included as GFA once at the lowest floor." Counted once only. |
| Service ducts | Counted once at the lowest floor if the vertical shaft is entirely void. But "If the service ducts are slabbed over at every floor, the service duct at each floor is included as GFA." Non-load-bearing fire-stop material is excluded. |
| AC ledges (non-strata) | Not counted up to 2.0m width measured perpendicularly from the external wall. Area beyond 2.0m is counted. |
| RC ledges for sun shading or firefighting | Excluded up to 2.0m width, provided there is no railing or parapet wall and the ledge is located at the external facade. Beyond 2.0m it is counted. |
| Lift lobbies on car park floors | Counted, "limited to an area equivalent to the size of the lift shaft...or to the actual size of the lift lobby, whichever is smaller." |
| Sky terraces | Exempt within a 45-degree line from the edge of the overhead projection. URA "may grant additional GFA exemption for residual areas beyond the 45-degree line (capped at 20% of the floor plate area)." |
Not counted or exempted
| Item | Rule |
|---|---|
| Voids | Excluded by the general principle. |
| Car parking lots | "Car parking lots are excluded from GFA except under the following circumstances": private strata-titled lots, or lots exceeding the upper bounds for commercial, hotel, mixed-use, residential in the Central Area, and business parks near transit. |
| Motorcycle parking lots | Excluded except when proposed as private strata lots, or in excess of LTA's mandatory requirements. |
| Driveways, car porches, garages, pick-up points | Excluded, along with residual car park areas, which are those "incapable of accommodating an additional car park lot." |
| Mechanised parking systems | Excluded if there are no fixed platforms and the system is common property managed by the MCST. |
| M&E floors | "M&E floors with headroom of up to 1.8m are excluded from GFA." |
| M&E rooms in fully sunken common basement car parks | Excluded, including bin centres, substations, energy storage systems and DCS or CCS equipment. |
| M&E spaces on common car park floors | Excluded where "enclosed by chain-link fencing or low parapet wall." |
| Rooftop service screening | "Non load bearing roof covers meant to screen off rooftop services...may be excluded from GFA." |
| Refuse chutes | "Refuse chutes are excluded from GFA." |
| Refuse and DV chambers | Excluded within fully sunken basement car parks. Outside basements, excluded where headroom is up to 1.8m. |
| Communal planter boxes | Excluded if maximum width 1.0m, minimum depth 500mm, and "sufficiently externalised". Otherwise "the entire planter box is included as GFA. There is no partial exclusion." |
| Sky terraces | Excluded subject to a minimum 40% perimeter openness (60% for predominant sky terraces), a minimum 5.0m depth throughout, permanent planting with sufficient soil depth, and access for all occupants via a communal lift or staircase. |
| Open courtyards and air wells in common areas | "Open courtyards and air wells located in the common areas are excluded from GFA." |
URA's own caveat applies to all of the above: "The principles and illustrations used in this Gross Floor Area (GFA) handbook is not exhaustive in covering all building designs", and URA reserves "the right to interpret GFA matters based on the specific design of a development proposal, depending on the merits of the proposal."
The recurring logic behind the list
The list looks arbitrary until you notice that the same four tests keep reappearing. Learn the tests and you can usually predict where a novel element will land, then check it against the handbook item.
- Headroom. 1.8m for M&E floors and refuse or DV chambers outside basements. 1.5m for floors under pitched roofs and for raised platforms.
- Width. 2.0m for AC ledges and RC ledges, measured perpendicularly from the external wall. 1.0m maximum for a communal planter box, with a 500mm minimum depth.
- Openness. 40% minimum perimeter openness for a sky terrace, 60% for a predominant sky terrace, and 40% continuous perimeter opening for a balcony under the incentive scheme.
- The strata test. Once a space sits inside a strata boundary, it usually counts. A planter box or a courtyard that is exempt in a common area is counted inside a strata unit.
Every one of those is a physical dimension that somebody has to be able to defend on site. That is a different problem from understanding the rule.
Strata area is GFA
This is the single most commonly inverted fact in the area. URA states: "All proposed strata areas will be computed as GFA. For example, if an AC ledge serving a residential unit is included as part of the strata area of the unit, the AC ledge will be computed as GFA." Strata area is included "regardless of whether the spaces are accessible or usable."
There is a carve-out. Such spaces "can continue to be considered for GFA exemption (notwithstanding their inclusion as strata area), subject to compliance with URA's prevailing guidelines for GFA exemptions", and URA's example is a covered walkway or sky terrace sitting inside a larger strata area.
Bonus GFA: the 10% ceiling and the sub-caps
URA publishes the same sentence on two separate pages: "The cumulative bonus GFA shall be kept within the overall budget of 10% above the Master Plan Gross Plot Ratio (GPR), or the maximum allowable GFA of the development." That is a cumulative budget across schemes, not 10% per scheme.
The named schemes:
- Non-residential and commercial: Community and Sports Facilities Scheme (CSFS); Rooftop ORA on Landscaped Roofs; Built Environment Transformation Scheme; ORA within Privately-Owned Public Spaces (POPS); District Cooling System or Centralised Cooling System Scheme; CBD Incentive Scheme; Strategic Development Incentive (SDI) Scheme.
- Residential, flats and condominiums: Balcony Incentive Scheme; Conserved Bungalows Scheme; Indoor Recreation Spaces Scheme; Built Environment Transformation Scheme; DCS or CCS Scheme.
The per-scheme caps URA publishes:
- Balconies: 7% of the proposed residential GFA of the development, subject to being located away from M&E areas, a continuous perimeter opening of at least 40%, and a minimum width of 1.5m measured from the external building wall.
- Private Enclosed Spaces (PES) and Private Roof Terraces (PRT): the same 7% cap.
- Indoor Recreation Spaces (IRS): 1% of total proposed residential GFA, with a minimum threshold of "more than 0.6% of the total proposed residential GFA or 10sqm (whichever is higher)".
Bonus GFA does not carry forward. URA states that it "shall not form the future development potential of the site upon redevelopment", and that "When the site is redeveloped in future, the additional GFA already used under the bonus GFA incentive schemes cannot be carried over."
GFA, strata area and "saleable area"
GFA is a development-intensity control computed for a whole development. Strata area demarcates ownership. Neither describes what a buyer walks around in, and the term that supposedly does has no official definition at all: URA's property market glossary contains no entry for saleable area, built-in area, strata area or gross floor area. Those are trade and marketing terms, not regulatory ones. That absence is itself the answer whenever someone asks you to reconcile a brochure figure against a planning figure.
Who computes, who lodges, who certifies, who approves
This is the part most often stated loosely, and stating it loosely misrepresents a protected professional title, so here it is precisely.
1. The Qualified Person computes and declares the GFA
A QP is a "Qualified Person (registered architect or engineer)". QPs must "clearly reflect both the GFA and strata boundaries on each of the floor plans submitted to URA" and verify that "all proposed strata areas have been duly computed as GFA." Missing strata boundary documentation may delay URA approval.
2. Only a Registered Surveyor can lodge the strata subdivision plan
URA is explicit: "Only a Registered Surveyor appointed by the owner can lodge the strata subdivision plan under the Plan Lodgment scheme."
3. Two separate declarations at strata subdivision
The Registered Surveyor declares compliance with conditions including setback deviations and layout and area requirements. The Qualified Person declares compliance with written permissions, building control approvals and floor area limits. Two professions, two declarations, neither substituting for the other.
4. SLA closes the loop
Applicants then apply to the Singapore Land Authority for land or strata title plan approval and subsequent registration. SLA states that "The completion of a property boundary survey happens when the Chief Surveyor approves the survey plan submitted and certified by the Registered Surveyor." The Strata Certified Plan is where the area figures end up: a table in the CPST shows the floor area, the void area if any, the sub-total area of each storey, the total strata void area and the total strata area of the lot.
URA adds that "Developers are strongly encouraged to involve surveyors early in the design process to firm up the proposed strata boundaries."
A 3D scanning or measured-survey firm certifies nothing here. It supplies the measured basis those professionals work from. A Registered Surveyor's endorsement, a Professional Engineer's structural assessment and a QP's declaration are statutory roles that a scan does not and cannot replace.
URA's GFA Verification service
URA runs a service specifically for this: "This service is provided to enable building owners/developers to verify the GFA of their existing or proposed development." It is voluntary and "an independent service which is delinked from development applications." Applications go to eservice.ura.gov.sg/gfaWeb.
Two conditions matter. Only a Qualified Person may apply, with the property owner's consent. And the submission format is specific: URA requires CAD or BIM calculation plans in .dwg, .dgn, .rvt or .pla, using Singapore CAD layering standards with dedicated layers for area included in GFA (AREAGFAA) and area excluded (AREAGFAD), plus "a summary of GFA breakdown by floors". URA's terms put the onus on the applicant: "The Customer shall ensure that any information posted...is true and accurate."
Read that as a workflow, not a formality. URA will verify GFA for an existing development, but only from a QP's CAD or BIM model, and the accuracy of that model is the applicant's responsibility. For an existing building with no reliable drawings, that model has to be produced from the building itself. Note also what this service is not: it is voluntary and applicant-initiated, so do not read it as URA re-measuring completed buildings on its own initiative.
Older developments and re-computation
Developments approved before 1 September 1989 were controlled by population density for residential and net floor area for commercial. URA states that "There is a need to convert the approved GFA of the developments to the standardised current GFA definition." For approvals on or after 1 September 1989, "there is no need to recompute the GFA for such developments." URA's page does not say who performs that re-computation, or what happens if the re-computed figure differs, so ask URA rather than assume.
When the built GFA does not match the approved GFA
URA states that "If this results in the proposed GFA exceeding the Master Plan control, URA will require the proposed GFA to be rectified (e.g. via an amendment application) before strata subdivision approval can be granted."
The mechanism that forces this is the QP's declaration. The QP must declare that "The floor area of the development of land does not exceed the quantum of floor area approved by the Competent Authority in the written permission granted for the development of land." A development that has grown beyond its approved GFA cannot make that declaration, which is what stops a subdivision until the discrepancy is regularised.
What a discrepancy costs
These are URA penalties under the Planning Act 1998. They are not BCA's and they are not the Building Control Act's: no BCA penalty figure for unauthorised building works was verified in our research, so do not transfer these numbers across. URA's penalty rates page states that "The civil penalty levied will be dependent on the amount of unauthorised retention works based on the 3 bands below."
| Band | Floor area of unauthorised retention works | Civil penalty | With an enforcement record |
|---|---|---|---|
| Band I | 0 to 50m² or less | 1× processing fee | 2× |
| Band II | More than 50m² up to 150m² | 4× | 8× |
| Band III | More than 150m² | 6× | 12× |
Where there is deception, URA states that "a higher civil penalty of up to 25 times the processing fees or $150,000 (whichever is lower) will be imposed." On the criminal side, URA's media release of 22 April 2026 states: "If found guilty under the Planning Act 1998, offenders may be liable to a fine of up to $500,000, or imprisonment for a term not exceeding 12 months, or both." Offenders may also be "required to reinstate and restore the building at its own cost."
Note the shape of the bands. The penalty scales with the floor area of the unauthorised works, and the step from Band II to Band III is 150m². Knowing your true areas is a financial question before it is a compliance one.
Where measurement fits, and where it does not
If you want to understand the GFA rules, you need URA's handbook, not a survey. Say that first, because it is true. Measurement earns its place only where a physical dimension of an existing building has to be established and defended. The specific cases:
- a GFA Verification application for an existing building, where URA requires a QP to submit a CAD or BIM calculation plan with AREAGFAA and AREAGFAD layers and holds the applicant responsible for its accuracy;
- a strata subdivision blocked on a GFA discrepancy, where URA requires rectification before approval;
- a pre-1 September 1989 development whose GFA needs converting to the current definition;
- a development approved before June 2023 being compared against a current computation under the middle-of-wall rule;
- an A&A or change-of-use submission where the QP must state existing GFA and no dependable as-built drawing exists;
- a bonus GFA condition that turns on a physical dimension: a 1.5m balcony width, a 40% perimeter opening, a 5.0m sky terrace depth, a 2.0m ledge, a 1.8m headroom;
- unauthorised retention works where the penalty band is decided by area.
In each of those, the deliverable is a measured model, not a certificate. As-built documentation produces the drawing set of the building as it stands, and Scan-to-BIM produces the Revit model in the file formats URA's verification service accepts. The QP still computes and declares the GFA. If your building has no dependable drawings and a submission is waiting on it, tell us what the QP has asked for. Where the record itself has failed, start with floor plan missing or wrong.