GFA Harmonisation: Why the Same Flat Is Suddenly 40 Square Feet Smaller

Put a 2021 two-bedder and a 2026 new launch of the "same" size side by side on a property portal and the older one often looks cheaper per square foot. Frequently it isn't — the two units are simply measured by different rulebooks. A quiet reform that took effect on 1 June 2023, called GFA harmonisation, changed what counts as saleable floor area. Post-2023 units exclude the air-con ledges and voids that older units still bundle into their quoted size, so a new launch reports fewer square feet and a higher price per square foot for the same money and the same usable space. Compare the headline PSF straight and you will misjudge value on both sides. Here is what the rule actually did, and the adjustment that puts an honest comparison back on the table. Methodology published. No spin.

What changed on 1 June 2023

Gross Floor Area is the number behind every brochure, valuation and plot-ratio calculation. Before mid-2023, Singapore's agencies each defined it slightly differently, and developers exploited the gaps. URA, the Building and Construction Authority, the Singapore Land Authority and the Civil Defence Force harmonised their definitions into one standard, applied to all development applications submitted from 1 June 2023 (and to Government Land Sales sites launched from 1 September 2022). Three changes matter to a buyer:

• All floor areas are now measured to the mid-point of the wall, one consistent rule across every agency.
• Air-con ledges kept as part of your unit now count as GFA; to keep them out, a developer must leave them as common property, capped at 2 metres wide. In practice, they moved out of your saleable area.
• Strata voids — the empty vertical air above a double-height living room — are excluded from strata area. Developers can no longer sell you volume you cannot stand on.

Industry estimates put air-con ledges at roughly 4% to 5% of a unit's saleable area before the change, and developer efficiency ratios that once ran at 99% to 100% were expected to settle near 95% afterwards. The first private project designed fully under the new rules was Lentor Mansion; every launch since follows the same standard.

Why the same flat lost 40 square feet

Strip out the ledges and the void and the quoted size falls, even though the room you can furnish is unchanged. On TRIBE's numbers, a 689 sqft pre-2023 two-bedroom restates to roughly 650 sqft harmonised — about 40 square feet, or 6%, gone on paper. A 1,000 sqft three-bedder restates to about 926 sqft, closer to 8%. The floor you walk on is identical; only the measuring tape changed.

You can see it in real stock. A three-bedroom at the pre-harmonisation Tembusu Grand was listed at 1,173 sqft; the comparable layout at the post-harmonisation Emerald of Katong — the same District 15 stretch, launched a year later — measured 969 sqft. That is 204 square feet, or 17%, smaller on paper. Be honest about the decomposition, though: harmonisation explains only about 87 of those square feet (the 8% band for a three-bedder). The rest — roughly 117 square feet — is developers genuinely designing smaller layouts to keep the total quantum affordable. Harmonisation is the measurement story; shrinking cheque-sizes is a separate, parallel one, and it pays to keep them apart.

The trap: headline PSF versus effective PSF

Here is where buyers go wrong. Because the harmonised unit reports less floor for the same price, its headline PSF looks higher — and anchoring on that figure makes new launches seem overpriced when they may not be.

Take the same S$1,900,000 outlay. A pre-2023 resale measured at 710 sqft prints at S$2,676 psf. Restated to its harmonised ~670 sqft, the identical space prints at S$2,836 psf. Same money, same walls — a S$160 psf difference created entirely by the measuring convention. The lesson is to compare quantum and usable layout first, and treat headline PSF as a number that now means two different things depending on which side of June 2023 the project sits.

Adjust before you compare

You cannot simply set a new launch's PSF against an older unit's raw PSF. To make the two comparable, lift the pre-2023 comp to a harmonised, "as-new" basis. The adjustment we apply on the New Project Scorecard is +6% for one- and two-bedders and +8% for three-bedders and larger — the same bands as the area restatement, worked on the PSF instead of the square footage.

A worked case. Dunearn House, a 2026 launch in District 11, is harmonised. Its natural leasehold benchmark, Fourth Avenue Residences, shares the same MRT station but completed in 2022 — non-harmonised — so its quoted areas still carry ledges and void. Its recent two-bedroom caveats read about S$2,522 psf. Lift that to a fresh 99-year lease (about +2.7% for the lease-decay gap) and then +6% for harmonisation, and the honest, like-for-like level is S$2,745 psf:

Now the comparison tells the truth. Against the raw S$2,522, Dunearn House's S$2,799 two-bedroom looks 11% dearer. Against the adjusted S$2,745, it is a 1.9% premium — a rounding error for a brand-new building — and the three-bedroom, at S$2,978 versus an adjusted S$3,102, actually comes in 4% below its older neighbour. Skip the adjustment and you would have talked yourself out of the cheaper unit.

What to actually do with this

Never compare a pre-2023 resale to a post-2023 launch on headline PSF. The two sizes are measured differently. Lift the older unit by roughly 6% (smaller units) to 8% (larger ones) before you compare, or compare on quantum and usable layout instead.

Read the floor plan, not just the number. On a pre-2023 plan, the hatched strips along the external walls — air-con ledges, planter boxes, bay windows — are area you paid for but cannot fully use. A harmonised plan carries fewer of them, which is why a newer unit often "lives bigger" than its quoted size suggests.

Don't assume the older unit is worse — or the newer one a rip-off. Some older layouts bought genuine volume and terraces that harmonised rules no longer permit, and plenty of buyers prize that openness. The reform did not make anything cheaper or dearer overnight; it changed what the tape measures. Your job is simply to compare like with like.

For the companion story — how these same rule changes reshaped the layouts themselves, from bay windows to queen-bed bedrooms — see From Bay Windows to Queen Beds. The measurement changed and the design changed with it; a careful buyer reads both.

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Sources: The 1 June 2023 effective date, the harmonised measurement rules, the air-con-ledge and strata-void changes, and the ~4–5% ledge share / ~95% post-reform efficiency estimate per URA circular DC22-09 and PropertyNet.SG. The Tembusu Grand (1,173 sqft) versus Emerald of Katong (969 sqft) three-bedroom comparison per the same PropertyNet analysis; the harmonisation-versus-layout decomposition is TRIBE's. Fourth Avenue Residences transacted PSF (URA caveats), the lease-decay adjustment (Bala's Table, ~90.7 years remaining) and the +6% / +8% GFA-harmonisation uplift per the TRIBE New Project Scorecard methodology, as set out in our Dunearn House review. Figures are illustrative; scores and adjustments are model outputs, not financial advice.

Silas Tan is a District Director at Huttons Asia and co-founder of TRIBE. He built the Resale Project Scorecard (RPS) and New Project Scorecard (NPS) on URA transacted data. This article is for informational purposes and does not constitute financial or investment advice. CEA Registration R000303I.